Method and device for performing registration in network in wireless communication system

ABSTRACT

A method for performing, by a user equipment (UE), a registration to a network in a wireless communication system is disclosed. Specifically, the UE performs a registration to a first public land mobile network (PLMN) via a first base station, receives an disaster related message applied to the first PLMN or applied to an area in which the UE is located when there is no service provided from the first PLMN, transmits a registration request message to a second PLMN providing an disaster roaming service based on the disaster related message, and receives, from the second PLMN, a response message to the registration request message. The UE is subscribed to the first PLMN, and the second PLMN is configured to provide the disaster roaming service to the UE based on a disaster applied to the first PLMN or applied to the area in which the UE is located.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage filing under 35 U.S.C. 371 ofInternational Application No. PCT/KR2020/000216, filed on Jan. 6, 2020,which claims the benefit of Korean Patent Application No.10-2019-0001399, filed on Jan. 4, 2019, and Korean Patent ApplicationNo. 10-2019-0049042, filed on Apr. 26, 2019, the contents of which areall hereby incorporated by reference herein in their entirety.

TECHNICAL FIELD

The present disclosure relates to a wireless communication system, andmore particularly to a method for performing, by a user equipment (UE)and a base station, UE's registration to a network in a wirelesscommunication system, and a device therefor.

BACKGROUND ART

In a wireless communication system, mobile communication systems havebeen developed to provide a voice service while ensuring the activity ofa user. However, the area of the mobile communication systems hasextended to a data service in addition to a voice. Due to the currentexplosive increase in traffic, there is a shortage of resources, andthus users demand a higher speed service. Accordingly, there is a needfor a more advanced mobile communication system.

Requirements for next-generation mobile communication systems need toable to support the accommodation of explosive data traffic, a dramaticincrease in data rate per user terminal, the accommodation of asignificant increase in the number of connected devices, very lowend-to-end latency, and high-energy efficiency. To this end, studieshave been conducted on various technologies such as dual connectivity,massive multiple input multiple output (MIMO), in-band full duplex,non-orthogonal multiple access (NOMA), super wideband support, anddevice networking.

DISCLOSURE Technical Problem

An object of the present disclosure is to provide a method forperforming roaming to a network of other available surrounding serviceprovider and providing services, when a UE is located in a serviceprovision area of a service provider to which the UE subscribes, but theservice provider cannot temporarily provide services.

Another object of the present disclosure is to provide a communicationsystem and method, in which a UE rapidly recognizes a problem in anetwork of a service operator, to which the UE subscribes, in a processin which the UE accesses a network of other service provider in anautomatic network selection mode, and the UE moves to a new network andreceives services without interruption of the service as much aspossible.

The technical objects to be achieved by the present disclosure are notlimited to those that have been described hereinabove merely by way ofexample, and other technical objects that are not mentioned can beclearly understood by those skilled in the art, to which the presentdisclosure pertains, from the following descriptions.

Technical Solution

In one aspect, there is provided a method for performing, by a userequipment (UE), a registration to a network in a wireless communicationsystem, the method comprising performing a registration to a firstpublic land mobile network (PLMN) via a first base station; when thereis no service provided from the first PLMN, receiving an disasterrelated message applied to the first PLMN or applied to an area in whichthe UE is located; transmitting a registration request message to asecond PLMN providing an disaster roaming service based on the disasterrelated message; and receiving, from the second PLMN, a response messageto the registration request message, wherein the UE is subscribed to thefirst PLMN, wherein the second PLMN is configured to provide thedisaster roaming service to the UE based on a disaster applied to thefirst PLMN or applied to the area in which the UE is located.

The disaster related message includes an indicator indicating that thedisaster roaming service is provided to UEs related to the first PLMN.

The disaster related message includes information representing that thedisaster roaming service is configured to be provided to the UE relatedto the first PLMN.

The disaster related message is a system information block (SIB) messagereceived to the UE according to a pre-configured periodicity.

The method further comprises transmitting an RRC connection requestmessage to a second base station connected to the second PLMN, andreceiving a response message to the RRC connection request message toestablish an RRC connection with the second PLMN via the second basestation. The RRC connection request message is transmitted due to adisaster roaming.

In another aspect, there is provided a user equipment (UE) performing aregistration to a network in a wireless communication system, the UEcomprising an RF module configured to transmit and receive a radiosignal; at least one processor functionally connected to the RF module;and at least one computer memory operationally connected to the at leastone processor, wherein the at least one computer memory is configuredto, upon execution, store instructions that allow the at least oneprocessor to perform a registration to a first public land mobilenetwork (PLMN) via a first base station; when there is no serviceprovided from the first PLMN, receive an disaster related messageapplied to the first PLMN or applied to an area in which the UE islocated; transmit a registration request message to a second PLMNproviding an disaster roaming service based on the disaster relatedmessage; and receive, from the second PLMN, a response message to theregistration request message, wherein the UE is subscribed to the firstPLMN, wherein the second PLMN is configured to provide the disasterroaming service to the UE based on a disaster applied to the first PLMNor applied to the area in which the UE is located.

The disaster related message includes an indicator indicating that thedisaster roaming service is provided to UEs related to the first PLMN.

The disaster related message includes information representing that thedisaster roaming service is configured to be provided to the UE relatedto the first PLMN.

The disaster related message is a system information block (SIB) messagereceived to the UE according to a pre-configured periodicity.

The at least one processor is configured to transmit an RRC connectionrequest message to a second base station connected to the second PLMN,and receive a response message to the RRC connection request message toestablish an RRC connection with the second PLMN via the second basestation, wherein the RRC connection request message is transmitted dueto a disaster roaming.

Advantageous Effects

The present disclosure can prevent interruption of service that a UE hasreceived from a specific network.

According to the present disclosure, a UE is capable of roaming movementto other network even in a disaster situation occurring in a specificnetwork, and thus a user can continuously use communication serviceseven in an interruption situation of communication services.

Effects that could be achieved with the present disclosure are notlimited to those that have been described hereinabove merely by way ofexample, and other effects and advantages of the present disclosure willbe more clearly understood from the following description by a personskilled in the art to which the present disclosure pertains.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the present disclosure and constitute a part of thedetailed description, illustrate embodiments of the present disclosureand serve to explain technical features of the present disclosuretogether with the description.

FIG. 1 illustrates an AI device 100 according to an embodiment of thepresent disclosure.

FIG. 2 illustrates an AI server 200 according to an embodiment of thepresent disclosure.

FIG. 3 illustrates an AI system 1 according to an embodiment of thepresent disclosure.

FIG. 4 illustrates various reference points.

FIG. 5 illustrates an example of a network structure of an evolveduniversal terrestrial radio access network (E-UTRAN) to which thepresent disclosure is applicable.

FIG. 6 illustrates an example of a general architecture of E-UTRAN andEPC.

FIG. 7 illustrates an example of a structure of a radio interfaceprotocol in a control plane between a UE and eNB.

FIG. 8 illustrates an example of a structure of a radio interfaceprotocol in a user plane between a UE and eNB.

FIG. 9 illustrates a general architecture of NR-RAN.

FIG. 10 illustrates an example of general functional split betweenNG-RAN and SGC.

FIG. 11 illustrates an example of a general architecture of 5G.

FIG. 12 is a flow chart illustrating an example of selecting a PLMNaccording to an embodiment of the present disclosure.

FIG. 13 is a flow chart illustrating a PLMN selection procedureaccording to method 2-1.

FIG. 14 is a flow chart illustrating a PLMN selection procedureaccording to method 4.

FIG. 15 is a flow chart illustrating a method for a UE to perform aregistration to a network in accordance with an embodiment of thepresent disclosure.

FIG. 16 is a flow chart illustrating a method for a base station toregister a UE to a network in accordance with an embodiment of thepresent disclosure.

FIG. 17 illustrates a block diagram of configuration of a communicationdevice according to an embodiment of the present disclosure.

FIG. 18 illustrates a block diagram of configuration of a communicationdevice according to an embodiment of the present disclosure.

FIG. 19 illustrates an example of a structure of a radio interfaceprotocol in a control plane between a UE and eNodeB.

MODE FOR INVENTION

Reference will now be made in detail to embodiments of the disclosure,examples of which are illustrated in the accompanying drawings. Adetailed description to be disclosed below together with theaccompanying drawing is to describe exemplary implementations of thepresent disclosure and not to describe a unique implementation forcarrying out the present disclosure. The detailed description belowincludes details to provide a complete understanding of the presentdisclosure. However, those skilled in the art know that the presentdisclosure can be carried out without the details.

In some cases, in order to prevent a concept of the present disclosurefrom being ambiguous, known structures and devices may be omitted orillustrated in a block diagram format based on core functions of eachstructure and device.

Description of Terms in the Present Disclosure

In the present disclosure, a base station (BS) refers to a terminal nodeof a network directly performing communication with a terminal. In thepresent disclosure, specific operations described to be performed by thebase station may be performed by an upper node of the base station, ifnecessary or desired. That is, it is obvious that in the networkconsisting of multiple network nodes including the base station, variousoperations performed for communication with the terminal can beperformed by the base station or network nodes other than the basestation. The ‘base station (BS)’ may be replaced by terms such as afixed station, Node B, evolved-NodeB (eNB), a base transceiver system(BTS), an access point (AP), and gNB (general NB). Further, a ‘terminal’may be fixed or movable and may be replaced by terms such as userequipment (UE), a mobile station (MS), a user terminal (UT), a mobilesubscriber station (MSS), a subscriber station (SS), an advanced mobilestation (AMS), a wireless terminal (WT), a machine type communication(MTC) device, a machine-to-machine (M2M) device, and a device-to-device(D2D) device.

In the present disclosure, downlink (DL) refers to communication fromthe base station to the terminal, and uplink (UL) refers tocommunication from the terminal to the base station. In the downlink, atransmitter may be a part of the base station, and a receiver may be apart of the terminal. In the uplink, the transmitter may be a part ofthe terminal, and the receiver may be a part of the base station.

Specific terms used in the following description are provided to helpthe understanding of the present disclosure, and may be changed to otherforms within the scope without departing from the technical spirit ofthe present disclosure.

The following technology may be used in various wireless access systems,such as code division multiple access (CDMA), frequency divisionmultiple access (FDMA), time division multiple access (TDMA), orthogonalfrequency division multiple access (OFDMA), single carrier-FDMA(SC-FDMA), and non-orthogonal multiple access (NOMA). The CDMA may beimplemented by radio technology such as universal terrestrial radioaccess (UTRA) or CDMA2000. The TDMA may be implemented by radiotechnology such as global system for mobile communications (GSM)/generalpacket radio service (GPRS)/enhanced data rates for GSM evolution(EDGE). The OFDMA may be implemented as radio technology such as IEEE802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and E-UTRA (evolvedUTRA). The UTRA is a part of a universal mobile telecommunication system(UMTS). 3rd generation partnership project (3GPP) long term evolution(LTE), as a part of an evolved UMTS (E-UMTS) using E-UTRA, adopts theOFDMA in downlink and adopts the SC-FDMA in uplink. LTE-advanced (A) isan evolution of the 3GPP LTE.

Embodiments of the present disclosure can be supported by standarddocuments disclosed in at least one of the IEEE 802, 3GPP, and 3GPP2specifications regarding wireless access systems. In other words, inembodiments of the present disclosure, those steps or parts omitted forthe purpose of clearly describing technical principles of the presentdisclosure can be supported by the standard documents. All the termsdisclosed in the present disclosure can also be explained by thestandard documents.

3GPP LTE/LTE-A is primarily described for clear description, buttechnical features of the present disclosure are not limited thereto.

Terms used in the present disclosure are defined as follows.

-   -   IP Multimedia Subsystem or IP Multimedia Core Network Subsystem        (IMS): an architectural framework for providing standardization        for delivering voice or other multimedia services on internet        protocol (IP).    -   Universal Mobile Telecommunication System (UMTS): the 3rd        generation mobile communication technology based on global        system for mobile communication (GSM) developed by the 3GPP.    -   Evolved Packet System (EPS): a network system consisting of an        evolved packet core (EPC), that is an internet protocol (IP)        based packet switched core network, and an access network such        as LTE and UTRAN. The EPS is a network of an evolved version of        UMTS.    -   NodeB: a base station of a UMTS network. It is installed        outdoor, and its coverage has a scale of a macro cell.    -   eNodeB: a base station of an EPS network. It is installed        outdoor, and its coverage has a scale of a macro cell.    -   Home NodeB: it is installed indoors as a base station of the        UMTS network, and its coverage has a scale of a macro cell.    -   Home eNodeB: it is installed indoors as a base station of the        EPS network, and its coverage has a scale of a macro cell.    -   User Equipment (UE): the UE may refer to terms such as a        terminal, a mobile equipment (ME), and a mobile station (MS).        The UE can be a portable device such as a notebook computer, a        cellular phone, a personal digital assistant (PDA), a smart        phone, and a multimedia device, or a non-portable device such as        a personal computer (PC) and a vehicle-mounted device. The term        of UE may refer to an MTC UE in the description related to MTC.    -   Machine Type Communication (MTC): communication performed by        machines without human intervention. It may be called        Machine-to-Machine (M2M) communication.    -   MTC terminal (MTC UE or MTC device or MTC apparatus): a terminal        (e.g., a vending machine, meter, etc.) having a communication        function (e.g., communication with an MTC server over PLMN) over        a mobile communication network and performing a MTC function.    -   Radio Access Network (RAN): a unit including a Node B and a        radio network controller (RNC) and eNodeB controlling the Node B        in the 3GPP network. The RAN exists at a UE end and provides a        connection to a core network.    -   Home Location Register (HLR)/Home Subscriber Server (HSS): a        database containing subscriber information within the 3GPP        network. The HSS can perform functions such as configuration        storage, identity management, user state storage, etc.    -   Public Land Mobile Network (PLMN): a network configured for the        purpose of providing mobile communication services to        individuals. The PLMN can be configured for each operator.    -   Non-Access Stratum (NAS): a functional layer for exchanging        signalling and a traffic message between a UE and a core network        at the UMTS and EPS protocol stacks. The NAS mainly functions to        support mobility of the UE and support a session management        procedure for establishing and maintaining an IP connection        between the UE and PDN GW.    -   Service Capability Exposure Function (SCEF): an entity within        the 3GPP architecture for service capability exposure that        provides a means to safely expose the services and capabilities        provided by 3GPP network interfaces.    -   Mobility Management Entity (MME): a network node in the EPS        network which performs mobility management and session        management functions.    -   Packet Data Network Gateway (PDN-GW): a network node in the EPS        network which performs UE IP address allocation, packet        screening and filtering, and charging data collection functions.    -   Serving GW (Serving Gateway): a network node in the EPS network        which performs functions such as mobility anchor, packet        routing, idle mode packet buffering, and triggering of paging        for the UE of MME.    -   Policy and Charging Rule Function (PCRF): a node in the EPS        network which performs policy decision to dynamically apply        differentiated QoS and billing policies per each service flow.    -   Open Mobile Alliance Device Management (OMA DM): A protocol        designed to manage mobile devices, such as mobile phones, PDAs,        and portable computers, which performs functions such as device        configuration, firmware upgrade, and error report    -   Operation Administration and Maintenance (OAM): A network        management function group which provides network fault        indication, performance information, and data and diagnostic        functions.    -   Packet Data Network (PDN): a network in which a server (e.g.,        MMS server, WAP server, etc.) supporting a specific service is        located.    -   PDN connection: a connection from the UE to the PDN, i.e., the        association (connection) between the UE represented by the IP        address and the PDN represented by the APN.    -   EPS Mobility Management (EMM): a sublayer of the NAS layer,        where the EMM may be in an “EMM-Registered” or        “EMM-Deregistered” state depending on whether the UE is network        attached or detached.    -   EMM Connection Management (ECM) connection: A signaling        connection for the exchange of NAS messages, established between        the UE and the MME. An ECM connection is a logical connection        consisting of an RRC connection between the UE and an eNB and S1        signaling connection between the eNB and the MME. When the ECM        connection is established/terminated, the RRC and S1 signaling        connections are established/terminated as well. To the UE, the        established ECM connection means having an RRC connection        established with the eNB, and to the MME, it means having an S1        signaling connection established with the eNB. Depending on        whether the NAS signaling connection, i.e., the ECM connection        is established, the ECM may have an “ECM-Connected” or        “ECM-Idle” state.    -   Access-Stratum (AS): It includes a protocol stack between the UE        and the radio (or access) network and is responsible for        transmitting data and network control signals.    -   NAS configuration Management Object (MO): A management object        (MO) used to configure the UE with parameters related to NAS        functionality.    -   Packet Data Network (PDN): A network in which a server (e.g.,        multimedia messaging service (MMS) server, wireless application        protocol (WAP) server, etc.) supporting a specific service is        located.    -   PDN connection: a logical connection between the UE and the PDN,        represented by one IP address (one IPv4 address and/or one IPv6        prefix).    -   Access Point Name (APN): a string that refers to or identifies a        PDN. In order to access the requested service or network, it        goes through a specific P-GW, which means a predefined name        (string) in the network so that the P-GW can be found. (e.g.,        internet.mnc012.mcc345.gprs)    -   Access Network Discovery and Selection Function (ANDSF): it is a        network entity and provides policies that allow the UE to        discover and select an available access on a per operator basis.    -   EPC path (or infrastructure data path): a user plane        communication path through EPC.    -   E-UTRAN Radio Access Bearer (E-RAB): it refers to the        concatenation of a S1 bearer and a corresponding data radio        bearer. If there is an E-RAB, there is an one-to-one mapping        between the E-RAB and the EPS bearer of the NAS.    -   GPRS Tunneling Protocol (GTP): a group of IP-based        communications protocols used to carry general packet radio        service (GPRS) within GSM, UMTS and LTE networks. Within the        3GPP architecture, GTP and proxy mobile IPv6-based interfaces        are specified on various interface points. GTP can be decomposed        into several protocols (e.g., GTP-C, GTP-U and GTP′). GTP-C is        used within a GPRS core network for signalling between gateway        GPRS support nodes (GGSN) and serving GPRS support nodes (SGSN).        GTP-C allows the SGSN to activate a session (e.g., PDN context        activation), deactivate the same session, adjust the quality of        service parameters, or renew a session for a subscriber, that        has just operated from another SGSN, for the user. GTP-U is used        to carry user data within the GPRS core network and between the        radio access network and the core network.    -   Cell as a radio resource: the 3GPP LTE/LTE-A system has used a        concept of a cell to manage radio resources, and a cell related        to the radio resource is distinguished from a cell of a        geographic area. The “cell” related to the radio resource is        defined as a combination of downlink (DL) resources and uplink        (UL) resources, i.e., a combination of DL carriers and UL        carriers. The cell may be configured with DL resource only or a        combination of DL resources and UL resources. If carrier        aggregation is supported, a linkage between a carrier frequency        of the DL resource and a carrier frequency of the UL resource        may be indicated by system information. Here, the carrier        frequency refers to a center frequency of each cell or carrier.        In particular, a cell operating on a primary frequency is called        a primary cell or Pcell, and a cell operating on a secondary        frequency is called a secondary cell or Scell. The Scell refers        to a cell that can be configured after radio resource control        (RRC) connection establishment is achieved and can be used for        providing additional radio resources. Depending on capabilities        of the UE, the Scell together with the Pcell can form a set of        serving cells for the UE. For the UE that is in a RRC_CONNECTED        state but is not configured with carrier aggregation, or does        not support carrier aggregation, there is only one serving cell        configured with only the Pcell. The “cell’ of the geographic        area can be understood as a coverage in which a node can provide        services using a carrier, and the “cell’ of the radio resource        is related to a bandwidth (BW) that is a frequency range        configured by the carrier. Since a downlink coverage that is a        range within which the node can transmit a valid signal and an        uplink coverage that is a range within which the node can        receive the valid signal from the UE depend on the carrier        carrying the corresponding signal, the coverage of the node is        associated with the coverage of the “cell’ of the radio resource        the node uses. Thus, the term “cell” may be used to sometimes        denote the coverage of the service by the node, sometimes denote        the radio resource, and sometimes denote a range that a signal        using the radio resources can reach with a valid strength.

The EPC is a key element of system architecture evolution (SAE) toimprove the performance of 3GPP technologies. The SAE corresponds to aresearch project to determine a network structure supporting mobilitybetween various kinds of networks. The SAE aims to provide an optimizedpacket-based system, for example, supporting various radio accesstechnologies on an IP basis and providing more improved data transfercapability.

More specifically, the EPC is a core network of an IP mobilecommunication system for the 3GPP LTE system and can supportpacket-based real-time and non-real time services. In the existingmobile communication system (i.e., in the 2nd or 3rd mobilecommunication system), functions of the core network have beenimplemented through two separate sub-domains including acircuit-switched (CS) sub-domain for voice and a packet-switched (PS)sub-domain for data. However, in the 3GPP LTE system that is anevolution of the 3rd mobile communication system, the CS and PSsub-domains have been unified into a single IP domain. That is, in the3GPP LTE system, a connection between UEs having IP capabilities can beconfigured via an IP-based base station (e.g., evolved Node B (eNodeB)),an EPC, and an application domain (e.g., IP multimedia subsystem (IMS)).In other words, the EPC is an essential architecture to implementend-to-end IP services.

The EPC may include various components, and FIG. 1 illustrates some ofthe EPC components, including a serving gateway (SGW), a packet datanetwork gateway (PDN GW), a mobility management entity (MME), a SGSN(serving GPRS (general packet radio service) supporting node), and anenhanced packet data gateway (ePDG).

The SGW (or S-GW) operates as a boundary point between a radio accessnetwork (RAN) and a core network, and is an element that functions tomaintain a data path between the eNB and the PDN GW. Further, if the UEmoves across areas served by the eNB, the SGW serves as a local mobilityanchor point. That is, packets can be routed through the SGW formobility within the E-UTRAN (evolved-universal mobile telecommunicationssystem (UMTS) terrestrial radio access network defined in 3GPP Release-8or later). The SGW may also serve as an anchor point for mobility withother 3GPP networks (RAN defined before 3GPP Release-8, for example,UTRAN or GERAN (global system for mobile communication (GSM)/enhanceddata rates for global evolution (EDGE) radio access network).

The PDN GW (or P-GW) corresponds to a termination point of a datainterface to a packet data network. The PDN GW can support policyenforcement features, packet filtering, charging support, and the like.In addition, the PDN GW can serve as an anchor point for mobilitymanagement between the 3GPP network and a non-3GPP network (e.g.,untrusted networks such as an interworking wireless local area network(I-WLAN) or trusted networks such as a code division multiple access(CDMA) network and Wimax).

Hereinafter, the present disclosure is described based on the termsdefined as above.

Three major requirement areas of 5G include (1) an enhanced mobilebroadband (eMBB) area, (2) a massive machine type communication (mMTC)area, and (3) an ultra-reliable and low latency communications (URLLC)area.

Some use cases may require multiple areas for optimization, and otheruse cases may focus on only one key performance indicator (KPI). 5Gsupports these various use cases in a flexible and reliable method.

eMBB is far above basic mobile Internet access and covers media andentertainment applications in abundant bidirectional tasks, cloud oraugmented reality. Data is one of key motive powers of 5G, and dedicatedvoice services may not be first seen in the 5G era. In 5G, it isexpected that voice will be processed as an application program using adata connection simply provided by a communication system. Major causesfor an increased traffic volume include an increase in the content sizeand an increase in the number of applications that require a high datatransfer rate. Streaming service (audio and video), dialogue type videoand mobile Internet connections will be used more widely as more devicesare connected to the Internet. Such many application programs requireconnectivity in which they are always turned on in order to pushreal-time information and notification to a user. A cloud storage andapplication suddenly increases in the mobile communication platform, andthis can be applied to both business and entertainment. Furthermore, thecloud storage is a special use case that tows the growth of an uplinkdata transfer rate. 5G is also used for remote business of cloud. When atactile interface is used, further lower end-to-end latency is requiredto maintain better user experiences. Entertainment, for example, cloudgame and video streaming are other key elements which increase a needfor the mobile broadband ability. Entertainment is essential in thesmartphone and tablet anywhere including high mobility environments,such as a train, a vehicle and an airplane. Another use case isaugmented reality and information search for entertainment. In thiscase, augmented reality requires very low latency and an instant amountof data.

Furthermore, one of the most expected 5G use cases relates to a functioncapable of smoothly connecting embedded sensors in all fields, that is,mMTC. Until 2020, it is expected that potential IoT devices will reach20.4 billions. The industry IoT is one of areas in which 5G performsmajor roles enabling smart city, asset tracking, smart utility,agriculture and security infra.

URLLC includes a new service which will change the industry throughremote control of major infra and a link with ultra reliability/lowavailable latency, such as a self-driving vehicle. A level ofreliability and latency is essential for smart grid control, industryautomation, robot engineering, drone control and adjustment.

Multiple use cases are described in more detail below.

5G can supplement fiber-to-the-home (FTTH) and cable-based broadband (orDOCSIS) as means for providing a stream evaluated from several hundredsof megabits per second to gigabits per second. Such fast speed isrequired to deliver TV with a resolution of 4K or more (6K, 8K or more)in addition to virtual reality and augmented reality. Virtual reality(VR) and augmented reality (AR) applications include immersive sportsgames. A specific application program may require a special networkconfiguration. For example, in VR games, in order for game companies tominimize latency, a core server may need to be integrated with the edgenetwork server of a network operator.

An automotive is expected to be an important and new motive power in 5G,along with many use cases for the mobile communication of an vehicle.For example, entertainment for a passenger requires a high capacity anda high mobility mobile broadband at the same time. This reason is thatfuture users continue to expect a high-quality connection regardless oftheir location and speed. Another use example of the automotive field isan augmented reality dashboard. The augmented reality dashboard overlapsand displays information, that identifies an object in the dark andnotifies a driver of the distance and movement of the object, over athing seen by the driver through a front window. In the future, awireless module enables communication between vehicles, informationexchange between a vehicle and a supported infrastructure, andinformation exchange between a vehicle and other connected devices(e.g., devices accompanied by a pedestrian). A safety system guidesalternative courses of a behavior so that a driver can drive moresafely, thereby reducing a danger of an accident. A next stage will be aremotely controlled or self-driven vehicle. This requires very reliable,very fast communication between different self-driven vehicles andbetween an automotive and infra. In the future, a self-driving vehiclecan perform all driving activities, and a driver will focus on onlyabnormal traffics, which cannot be identified by a vehicle itself.Technical requirements of a self-driving vehicle require ultra-lowlatency and ultra-high speed reliability so that traffic safety isincreased up to a level which cannot be achieved by a person.

A smart city and smart home mentioned as a smart society will beembedded as a high-density radio sensor network. The distributed networkof intelligent sensors will identify the cost of a city or home and acondition for energy-efficient maintenance. Similar configuration may beperformed for each home. All of a temperature sensor, a window andheating controller, a burglar alarm and home appliances are wirelesslyconnected. Many of these sensors are typically a low data transfer rate,low energy and low cost. However, for example, real-time HD video may berequired for a specific type of device for surveillance.

The consumption and distribution of energy including heat or gas arehighly distributed and thus require automated control of a distributedsensor network. A smart grid collects information, and interconnectssuch sensors using digital information and a communication technology sothat the sensors operate based on the information. The information mayinclude the behaviors of suppliers and consumers, and thus the smartgrid may improve the distribution of fuel, such as electricity, in anefficient, reliable, economical, production-sustainable and automatedmanner. The smart grid may be considered to be another sensor networkwith low latency.

A health part owns many application programs which reap the benefits ofmobile communication. A communication system can support remotetreatment providing clinical treatment at a distant place. This helps toreduce a barrier for the distance and can improve access to medicalservices which are not continuously used at remote farming areas.Furthermore, this is used to save life in important treatment and anemergency condition. A radio sensor network based on mobilecommunication can provide remote monitoring and sensors for parameters,such as the heart rate and blood pressure.

Radio and mobile communication becomes increasingly important in theindustry application field. Wiring requires a high installation andmaintenance cost. Accordingly, the possibility that a cable will bereplaced with reconfigurable radio links is an attractive opportunity inmany industrial fields. However, achieving the possibility requires thata radio connection operates with latency, reliability and capacitysimilar to those of the cable and that management is simplified. Lowlatency and a low error probability is a new requirement for aconnection to 5G.

Logistics and freight tracking is an important use case for mobilecommunication, which enables the tracking inventory and packagesanywhere using a location-based information system. The logistics andfreight tracking use case typically demands a low data speed, butrequires a wide area and reliable location information.

Embodiments of the present disclosure to be described below can beimplemented through the combination or the modification in order to meetthe 5G requirements described above.

The following is described in detail in relation to the technical fieldto which embodiments of the present disclosure to be described below canbe applied.

Artificial Intelligence (AI)

Artificial intelligence means the field in which artificial intelligenceor methodology capable of making the artificial intelligence isresearched. Machine learning means the field in which various problemshandled in the artificial intelligence field are defined and methodologyfor solving the problems is researched. Machine learning is also definedas an algorithm for improving performance of a task through continuousexperiences for the task.

An artificial neural network (ANN) is a model used in machine learning,and may refer to the entire model with a problem-solving ability whichconsists of artificial neurons (nodes) forming a network through acombination of synapses. The artificial neural network may be defined bya connection pattern between neurons of different layers, a learningprocess of updating a model parameter, and an activation function forgenerating an output value.

The artificial neural network may include an input layer, an outputlayer, and optionally one or more hidden layers. Each layer includes oneor more neurons. The artificial neural network may include a synapseconnecting neurons. In the artificial neural network, each neuron mayoutput a function value of an activation function for input signals,weights, and bias that are input through a synapse.

A model parameter means a parameter determined through learning, andincludes the weight of a synapse connection and the bias of a neuron.Furthermore, a hyper parameter refers to a parameter that shall beconfigured before learning in a machine learning algorithm, and includesa learning rate, the number of times of repetitions, a mini-deploymentsize, and an initialization function.

The purpose of learning of the artificial neural network may beconsidered to determine a model parameter that minimizes a lossfunction. The loss function may be used as an index for determining anoptimal model parameter in the learning process of an artificial neuralnetwork.

Machine learning may be classified into supervised learning,unsupervised learning, and reinforcement learning based on a learningmethod.

Supervised learning means a method of training an artificial neuralnetwork in the state in which a label for learning data has been given.The label may mean an answer (or a result value) that must be deduced byan artificial neural network when learning data is input to theartificial neural network. Unsupervised learning may mean a method oftraining an artificial neural network in the state in which a label forlearning data has not been given. Reinforcement learning may mean alearning method in which an agent defined within an environment istrained to select a behavior or behavior sequence that maximizesaccumulated compensation in each state.

Machine learning implemented as a deep neural network (DNN) including aplurality of hidden layers, among artificial neural networks, is alsocalled deep learning. The deep learning is part of the machine learning.Hereinafter, the machine learning is used as a meaning including thedeep learning.

Robot

A robot may mean a machine that automatically processes a given task oroperates based on an autonomously owned ability. Particularly, a robothaving a function for recognizing and autonomously determining anenvironment and performing an operation may be called an intelligentrobot.

The robot may be classified for industry, medical treatment, home, andmilitary based on its use purpose or field.

The robot includes a driver including an actuator or motor, and canperform various physical operations, such as moving a robot joint.Furthermore, a movable robot includes a wheel, a brake, a propeller,etc. in the driver, and may run on the ground or fly in the air throughthe driver.

Self-Driving (Autonomous-Driving)

Self-driving means a technology for autonomous driving. A self-drivingvehicle means a vehicle that runs without user manipulation or by user'sminimum manipulation.

For example, self-driving may include all of a technology formaintaining a driving lane, a technology for automatically controllingspeed such as adaptive cruise control, a technology for automaticallydriving along a fixed path, a technology for automatically setting anddriving a path when a destination is set, and the like.

A vehicle includes all of a vehicle having only an internal combustionengine, a hybrid vehicle including both an internal combustion engineand an electric motor, and an electric vehicle having only an electricmotor, and may include a train, a motorcycle, etc. in addition to thevehicles.

In this instance, the self-driving vehicle may be considered as a robothaving a self-driving function.

Extended Reality (XR)

Extended reality collectively refers to virtual reality (VR), augmentedreality (AR), and mixed reality (MR). The VR technology provides anobject or background of the real world as a CG image only. The ARtechnology provides a virtually produced CG image on an actual thingimage. The MR technology is a computer graphics technology for mixingand combining virtual objects with the real world and providing them.

The MR technology is similar to the AR technology in that it shows areal object and a virtual object together. However, there is adifference in that a virtual object is used to supplement a real objectin the AR technology, and on the other hand, a virtual object and a realobject are used as the same character in the MR technology.

The XR technology can be applied to a head-mount display (HMD), ahead-up display (HUD), a mobile phone, a tablet PC, a laptop, a desktop,TV, a digital signage, and the like. A device to which the XR technologyis applied may be called an XR device.

FIG. 1 illustrates an AI device 100 according to an embodiment of thepresent disclosure.

The AI device 100 may be implemented as a fixed device or mobile device,such as TV, a projector, a mobile phone, a smartphone, a desktopcomputer, a notebook, a terminal for digital broadcasting, a personaldigital assistants (PDA), a portable multimedia player (PMP), anavigator, a tablet PC, a wearable device, a set-top box (STB), a DMBreceiver, a radio, a washing machine, a refrigerator, a desktopcomputer, a digital signage, a robot, and a vehicle.

Referring to FIG. 1 , the AI device 100 may include a communication unit110, an input unit 120, a learning processor 130, a sensing unit 140, anoutput unit 150, a memory 170, and a processor 180.

The communication unit 110 may transmit and receive data to and fromexternal devices, such as other AI devices 100 a to 100 e or an AIserver 200, using wired and wireless communication technologies. Forexample, the communication unit 110 may transmit and receive sensorinformation, a user input, a learning model, and a control signal to andfrom the external devices.

Examples of communication technologies used by the communication unit110 include a global system for mobile communication (GSM), codedivision multi access (CDMA), long term evolution (LTE), 5G, a wirelessLAN (WLAN), wireless-fidelity (Wi-Fi), Bluetooth™ radio frequencyidentification (RFID), infrared data association (IrDA), ZigBee, nearfield communication (NFC), etc.

The input unit 120 may obtain various types of data.

The input unit 120 may include a camera for an image signal input, amicrophone for receiving an audio signal, a user input unit forreceiving information from a user, etc. Herein, the camera or themicrophone is treated as a sensor, and thus a signal obtained from thecamera or the microphone may be referred to as sensing data or sensorinformation.

The input unit 120 can obtain learning data for model learning and inputdata to be used when an output is obtained using a learning model. Theinput unit 120 can obtain not-processed input data. In this case, theprocessor 180 or the learning processor 130 can extract an input featureby performing pre-processing on the input data.

The learning processor 130 may be trained by a model constructed by anartificial neural network using learning data. In this case, the trainedartificial neural network may be called a learning model. The learningmodel may be used to deduce a result value of new input data notlearning data, and the deduced value may be used as a base forperforming a given operation.

The learning processor 130 can perform AI processing along with alearning processor 240 of the AI server 200.

The learning processor 130 may include a memory integrated orimplemented in the AI device 100. Alternatively, the learning processor130 may be implemented using the memory 170, an external memory directlycoupled to the AI device 100, or a memory maintained in an externaldevice.

The sensing unit 140 can obtain at least one of internal information ofthe AI device 100, surrounding environment information of the AI device100, or user information using various sensors.

Examples of sensors included in the sensing unit 140 include a proximitysensor, an illumination sensor, an acceleration sensor, a magneticsensor, a gyro sensor, an inertia sensor, an RGB sensor, an IR sensor, afingerprint recognition sensor, an ultrasonic sensor, a photo sensor, amicrophone, LIDAR, and a radar.

The output unit 150 can generate an output related to a visual sense, anauditory sense or a tactile sense.

The output unit 150 may include a display for outputting visualinformation, a speaker for outputting auditory information, and a hapticmodule for outputting tactile information.

The memory 170 can store data supporting various functions of the AIdevice 100. For example, the memory 170 can store input data obtained bythe input unit 120, learning data, a learning model, a learning history,etc.

The processor 180 can determine at least one executable operation of theAI device 100 based on information that is determined or generated usinga data analysis algorithm or a machine learning algorithm. Furthermore,the processor 180 can perform operation determined by controlling thecomponents of the AI device 100.

To this end, the processor 180 can request, search, receive, or utilizedata of the learning processor 130 or the memory 170, and can controlthe components of the AI device 100 to execute a predicted operation oran operation determined to be preferred, among the at least oneexecutable operation.

In this case, if association with an external device is necessary toperform the determined operation, the processor 180 may generate acontrol signal for controlling the corresponding external device andtransmit the generated control signal to the corresponding externaldevice.

The processor 180 can obtain intention information for a user input andtransmit user requirements based on the obtained intention information.

The processor 180 can obtain the intention information corresponding tothe user input using at least one of a speech to text (STT) engine forconverting a voice input into a text string or a natural languageprocessing (NLP) engine for obtaining intention information of a naturallanguage.

In this case, at least one of the STT engine or the NLP engine may beconstructed by an artificial neural network of which at least a portionis trained according to a machine learning algorithm. Furthermore, atleast one of the STT engine or the NLP engine may have been trained bythe learning processor 130, may have been trained by the learningprocessor 240 of the AI server 200, or may have been trained bydistributed processing thereof.

The processor 180 may collect history information including thefeedback, etc. of the user for the operation contents or an operation ofthe AI device 100, and may store the history information in the memory170 or the learning processor 130 or may transmit the historyinformation to an external device such as the AI server 200. Thecollected history information may be used to update a learning model.

The processor 180 may control at least some of the components of the AIdevice 100 in order to run an application program stored in the memory170. Moreover, the processor 180 may combine and operate two or more ofthe components included in the AI device 100 in order to run theapplication program.

FIG. 2 illustrates an AI server 200 according to an embodiment of thepresent disclosure.

Referring to FIG. 2 , the AI server 200 may refer to a device which istrained by an artificial neural network using a machine learningalgorithm or which uses a trained artificial neural network. Herein, theAI server 200 consists of a plurality of servers and may performdistributed processing and may be defined as a 5G network. Further, theAI server 200 may be included as a partial configuration of the AIdevice 100 and may perform at least a part of AI processing.

The AI server 200 may include a communication unit 210, a memory 230, alearning processor 240, and a processor 260.

The communication unit 210 may transmit and receive data to and from anexternal device such as the AI device 100.

The memory 230 may include a model storage unit 231. The model storageunit 231 may store a model (or artificial neural network 231 a) which isbeing trained or has been trained through the learning processor 240.

The learning processor 240 may train the artificial neural network 231 ausing learning data. The learning model may be used in the state inwhich it has been mounted on the AI server 200 of the artificial neuralnetwork, or may be mounted on an external device such as the AI device100 and used.

The learning model may be implemented as hardware, software or acombination of hardware and software. If a part or all of the learningmodel is implemented as software, one or more instructions constructingthe learning model may be stored in the memory 230.

The processor 260 may deduce a result value of new input data using thelearning model and generate a response or a control command based on thededuced result value.

FIG. 3 illustrates an AI system 1 according to an embodiment of thepresent disclosure.

Referring to FIG. 3 , in the AI system 1, at least one of the AI server200, a robot 100 a, a self-driving vehicle 100 b, an XR device 100 c, asmartphone 100 d, or home appliances 100 e is connected to a cloudnetwork 10. The robot 100 a, the self-driving vehicle 100 b, the XRdevice 100 c, the smartphone 100 d or the home appliances 100 e to whichthe AI technology is applied may be called AI devices 100 a to 100 e.

The cloud network 10 may constitute part of cloud computing infra or maymean a network present within cloud computing infra. The cloud network10 may be configured using the 3G network, the 4G or long term evolution(LTE) network, or the 5G network.

That is, the devices 100 a to 100 e and 200 constituting the AI system 1may be interconnected over the cloud network 10. In particular, thedevices 100 a to 100 e and 200 may communicate with each other through abase station, or may directly communicate with each other without theintervention of the base station.

The AI server 200 may include a server for performing AI processing anda server for performing calculation on big data.

The AI server 200 is connected to at least one of the robot 100 a, theself-driving vehicle 100 b, the XR device 100 c, the smartphone 100 d orthe home appliances 100 e, that are AI devices constituting the AIsystem 1, over the cloud network 10, and may help at least part of theAI processing of the connected AI devices 100 a to 100 e.

The AI server 200 can train an artificial neural network based on amachine learning algorithm in place of the AI devices 100 a to 100 e,and can directly store a learning model or transmit the learning modelto the AI devices 100 a to 100 e.

The AI server 200 can receive input data from the AI devices 100 a to100 e, deduce a result value of the received input data using thelearning model, generate a response or control command based on thededuced result value, and transmit the response or control command tothe AI devices 100 a to 100 e.

Alternatively, the AI devices 100 a to 100 e can directly deduce aresult value of input data using a learning model, and can generate aresponse or a control command based on the deduced result value.

Various implementations of the AI devices 100 a to 100 e to which theabove-described technologies are applied are described below. Herein,the AI devices 100 a to 100 e illustrated in FIG. 3 may be considered asdetailed implementations of the AI device 100 illustrated in FIG. 1 .

AI and Robot to which the Present Disclosure is Applicable

The AI technology is applied to the robot 100 a, and the robot 100 a maybe implemented as a guidance robot, a transport robot, a cleaning robot,a wearable robot, an entertainment robot, a pet robot, an unmannedaerial robot, etc.

The robot 100 a may include a robot control module for controlling anoperation. The robot control module may mean a software module or a chipin which a software module is implemented using hardware.

The robot 100 a may obtain status information of the robot 100 a, detect(recognize) a surrounding environment and an object, generate map data,determine a moving path and a running plan, determine a response to auser interaction, or determine an operation, using sensor informationobtained from various types of sensors.

The robot 100 a may use sensor information obtained by at least onesensor of LIDAR, a radar, and a camera in order to determine the movingpath and the running plan.

The robot 100 a may perform the above operations using a learning modelconsisting of at least one artificial neural network. For example, therobot 100 a may recognize a surrounding environment and an object usingthe learning model, and determine an operation using the recognizedsurrounding environment information or object information. Herein, thelearning model may have been directly trained in the robot 100 a or mayhave been trained in an external device such as the AI server 200.

The robot 100 a may directly generate results using the learning modeland perform an operation, but may perform an operation by transmittingsensor information to an external device such as the AI server 200 andreceiving results generated in response to this.

The robot 100 a may determine the moving path and the running plan usingat least one of map data, object information detected from sensorinformation, or object information obtained from the external device.The robot 100 a may run along the determined moving path and runningplan by controlling the driver.

The map data may include object identification information for variousobjects disposed in the space in which the robot 100 a moves. Forexample, the map data may include object identification information forfixed objects, such as a wall and a door, and movable objects, such as aflowerport and a desk. Furthermore, the object identificationinformation may include a name, a type, a distance, a location, etc.

Furthermore, the robot 100 a may perform an operation or run bycontrolling the driver based on a user's control/interaction. In thiscase, the robot 100 a may obtain intention information of interactionaccording to a user's behavior or voice utterance, may determine aresponse based on the obtained intention information, and may perform anoperation.

AI and Self-Driving to which the Present Disclosure is Applicable

The AI technology is applied to the self-driving vehicle 100 b, and theself-driving vehicle 100 b may be implemented as a mobile robot, avehicle, an unmanned aerial vehicle, etc.

The self-driving vehicle 100 b may include a self-driving control modulefor controlling a self-driving function. The self-driving control modulemay mean a software module or a chip in which a software module has beenimplemented using hardware. The self-driving control module may beincluded in the self-driving vehicle 100 b as the component of theself-driving vehicle 100 b, but may be configured as separate hardwareoutside the self-driving vehicle 100 b and connected to the self-drivingvehicle 100 b.

The self-driving vehicle 100 b may obtain status information of theself-driving vehicle 100 b, detect (recognize) a surrounding environmentand object, generate map data, determine a moving path and a runningplan, or determine an operation, using sensor information obtained fromvarious types of sensors.

In order to determine the moving path and the running plan, theself-driving vehicle 100 b may use sensor information obtained from atleast one sensor among LIDAR, a radar and a camera, in the same manneras the robot 100 a.

Particularly, the self-driving vehicle 100 b may recognize anenvironment or an object in an area in which a sight is blocked or anarea of a predetermined distance or more by receiving sensor informationfrom external devices, or may receive information that is directlyrecognized from the external devices.

The self-driving vehicle 100 b may perform the above operations using alearning model consisting of at least one artificial neural network. Forexample, the self-driving vehicle 100 b may recognize a surroundingenvironment and object using a learning model and determine a runningpath using the recognized surrounding environment information or objectinformation. Herein, the learning model may have been directly trainedin the self-driving vehicle 100 b or may have been trained in anexternal device such as the AI server 200.

In this instance, the self-driving vehicle 100 b may directly generateresults using the learning model to perform an operation, but mayperform an operation by transmitting sensor information to an externaldevice such as the AI server 200 and receiving results generated inresponse to this.

The self-driving vehicle 100 b may determine a moving path and a runningplan using at least one of map data, object information detected fromsensor information, or object information obtained from an externaldevice. The self-driving vehicle 100 b may run based on the determinedmoving path and running plan by controlling the driver.

The map data may include object identification information for variousobjects disposed in the space (e.g., road) on which the self-drivingvehicle 100 b runs. For example, the map data may include objectidentification information for fixed objects, such as a streetlight, arock, and a building, etc., and mobile objects, such as a vehicle and apedestrian. Furthermore, the object identification information mayinclude a name, a type, a distance, a location, etc.

Furthermore, the self-driving vehicle 100 b may perform an operation orrun by controlling the driver based on a user's control/interaction. Inthis case, the self-driving vehicle 100 b may obtain intentioninformation of an interaction according to a user' behavior or voicespeaking, may determine a response based on the obtained intentioninformation, and may perform an operation.

AI and XR to which the Present Disclosure is Applicable

The AI technology is applied to the XR device 100 c, and the XR device100 c may be implemented as a head-mount display (HMD), a head-updisplay (HUD) provided in a vehicle, television, a mobile phone, asmartphone, a computer, a wearable device, home appliances, a digitalsignage, a vehicle, a fixed robot or a mobile robot.

The XR device 100 c may generate location data and attributes data forthree-dimensional (3D) points by analyzing 3D point cloud data or imagedata obtained through various sensors or from an external device, mayobtain information on a surrounding space or real object based on thegenerated location data and attributes data, and may output an XR objectby rendering the XR object. For example, the XR device 100 c may outputan XR object including additional information for a recognized object bymaking the XR object correspond to the corresponding recognized object.

The XR device 100 c may perform the above operations using a learningmodel consisting of at least one artificial neural network. For example,the XR device 100 c may recognize a real object in 3D point cloud dataor image data using a learning model, and may provide informationcorresponding to the recognized real object. In this case, the learningmodel may have been directly trained in the XR device 100 c or may havebeen trained in an external device such as the AI server 200.

In this instance, the XR device 100 c may directly generate resultsusing a learning model and perform an operation, but may perform anoperation by transmitting sensor information to an external device suchas the AI server 200 and receiving results generated in response tothis.

AI, Robot and Self-Driving to which the Present Disclosure is Applicable

The AI technology and the self-driving technology are applied to therobot 100 a, and the robot 100 a may be implemented as a guidance robot,a transport robot, a cleaning robot, a wearable robot, an entertainmentrobot, a pet robot, an unmanned aerial robot, etc.

The robot 100 a to which the AI technology and the self-drivingtechnology are applied may mean a robot itself having a self-drivingfunction, or may mean the robot 100 a interacting with the self-drivingvehicle 100 b.

The robot 100 a with the self-driving function may collectively refer todevices that move by itself along a given path without control of a useror determine by itself a moving path and move.

The robot 100 a with the self-driving function and the self-drivingvehicle 100 b may use a common sensing method to determine one or moreof a moving path or a running plan. For example, the robot 100 a withthe self-driving function and the self-driving vehicle 100 b maydetermine one or more of a moving path or a running plan usinginformation sensed through LIDAR, a radar, a camera, etc.

The robot 100 a interacting with the self-driving vehicle 100 b ispresent separately from the self-driving vehicle 100 b, and may performan operation associated with a self-driving function inside or outsidethe self-driving vehicle 100 b or an operation associated with a usergot in the self-driving vehicle 100 b.

In this case, the robot 100 a interacting with the self-driving vehicle100 b may control or assist the self-driving function of theself-driving vehicle 100 b by obtaining sensor information in place ofthe self-driving vehicle 100 b and providing the sensor information tothe self-driving vehicle 100 b, or by obtaining sensor information,generating surrounding environment information or object information,and providing the surrounding environment information or objectinformation to the self-driving vehicle 100 b.

Alternatively, the robot 100 a interacting with the self-driving vehicle100 b may control the function of the self-driving vehicle 100 b bymonitoring a user got in the self-driving vehicle 100 b or through aninteraction with a user. For example, if it is determined that a driveris in a drowsiness state, the robot 100 a may activate the self-drivingfunction of the self-driving vehicle 100 b or assist control of adriving unit of the self-driving vehicle 100 b. Herein, the function ofthe self-driving vehicle 100 b controlled by the robot 100 a may includea function provided by a navigation system or audio system providedwithin the self-driving vehicle 100 b, in addition to a self-drivingfunction simply.

Alternatively, the robot 100 a interacting with the self-driving vehicle100 b may provide information to the self-driving vehicle 100 b or mayassist a function outside the self-driving vehicle 100 b. For example,the robot 100 a may provide the self-driving vehicle 100 b with trafficinformation including signal information, etc., as in a smart trafficlight, and may automatically connect an electric charger to a fillinginlet through an interaction with the self-driving vehicle 100 b as inthe automatic electric charger of an electric vehicle.

AI, Robot and XR to which the Present Disclosure is Applicable

The AI technology and the XR technology are applied to the robot 100 a,and the robot 100 a may be implemented as a guidance robot, a transportrobot, a cleaning robot, a wearable robot, an entertainment robot, a petrobot, an unmanned aerial robot, a drone, etc.

The robot 100 a to which the XR technology is applied may mean a robotthat is a target of control/interaction within an XR image. In thiscase, the robot 100 a is different from the XR device 100 c, and theymay operate in conjunction with each other.

If the robot 100 a that is a target of control/interaction within the XRimage obtains sensor information from sensors including a camera, therobot 100 a or the XR device 100 c may generate an XR image based on thesensor information, and the XR device 100 c may output the generated XRimage. Furthermore, the robot 100 a may operate based on a controlsignal received through the XR device 100 c or a user's interaction.

For example, a user may identify a corresponding XR image at time of therobot 100 a remotely operating in conjunction through an external devicesuch as the XR device 100 c, may adjust a self-driving path of the robot100 a through an interaction, may control an operation or driving, ormay identify information of a surrounding object.

AI, Self-Driving and XR to which the Present Disclosure is Applicable

The AI technology and the XR technology are applied to the self-drivingvehicle 100 b, and the self-driving vehicle 100 b may be implemented asa mobile robot, a vehicle, an unmanned aerial vehicle, etc.

The self-driving vehicle 100 b to which the XR technology is applied maymean a self-driving vehicle provided with a means for providing an XRimage or a self-driving vehicle that is a target of control/interactionwithin the XR image. Particularly, the self-driving vehicle 100 b thatis the target of control/interaction within the XR image is differentfrom the XR device 100 c, and they may operate in conjunction with eachother.

The self-driving vehicle 100 b provided with the means for providing theXR image may obtain sensor information from sensors including a camera,and may output the XR image generated based on the obtained sensorinformation. For example, the self-driving vehicle 100 b includes anHUD, and may provide a passenger with an XR object corresponding to areal object or an object within a screen by outputting an XR image.

In this case, when the XR object is output to the HUD, at least a partof the XR object may be output to overlap with a real object towardwhich a passenger's view is directed. On the other hand, when the XRobject is output to a display included within the self-driving vehicle100 b, at least a part of the XR object may be output to overlap with anobject within a screen. For example, the self-driving vehicle 100 b mayoutput XR objects corresponding to objects, such as a carriageway, othervehicles, a traffic light, a signpost, a two-wheeled vehicle, apedestrian, and a building.

If the self-driving vehicle 100 b that is a target ofcontrol/interaction within an XR image obtains sensor information fromsensors including a camera, the self-driving vehicle 100 b or the XRdevice 100 c may create an XR image based on the sensor information, andthe XR device 100 c may output the created XR image. Furthermore, theself-driving vehicle 100 b may operate based on a control signalreceived through an external device, such as the XR device 100 c, or auser's interaction.

5G System Architecture to which the Present Disclosure is Applicable

A 5G system is an advanced technology from 4G LTE mobile communicationtechnology and supports a new radio access technology (RAT), extendedlong term evolution (eLTE) as an extended technology of LTE, non-3GPPaccess (e.g., wireless local area network (WLAN) access), etc. throughthe evolution or a clean-state structure of an existing mobilecommunication network structure.

The 5G system is defined as service-based, and the interaction betweennetwork functions (NFs) in architecture for the 5G system can berepresented in two ways as follows.

-   -   Reference point representation: shows the interaction between NF        services in NFs described by a point-to-point reference point        (e.g., N11) between two NFs (e.g., AMF and SMF).    -   Service-based representation: network functions (e.g., AMF)        within a control plane (CP) enable other authorized network        functions to access their services. This representation also        includes a point-to-point reference point, if necessary.

Overview of 3GPP System

FIG. 4 illustrates various reference points.

In an example of a network structure illustrated in FIG. 4 , the SGW andthe PDN GW are configured as separate gateways, but the two gateways maybe implemented according to a single gateway configuration option.

The MME is an element to perform signaling and control functions forsupporting access to the network connection of the UE, allocation,tracking, paging, roaming, and handover of network resources, and so on.The MME controls control plane functions related to subscribers andsession management. The MME manages a large number of eNBs and performssignaling of the conventional gateway selection for handover to other2G/3G networks. Further, the MME performs functions of securityprocedures, terminal-to-network session handling, idle terminal locationmanagement, etc.

The SGSN handles all packet data such as mobility management andauthentication of the user for another 3GPP network (e.g., GPRSnetwork).

The ePDG serves as a security node for an untrusted non-3GPP network(e.g., I-WLAN, WiFi hotspot, etc.).

As described with reference to FIG. 4 , the UE with IP capability canaccess the IP service network (e.g., IMS) provided by a service provider(i.e., operator) via various components within the EPC based on thenon-3GPP access as well as the 3GPP access.

For example, reference points such as S1-U and S1-MME can connect twofunctions present in different functional entities. The 3GPP systemdefines a conceptual link connecting two functions present in differentfunctional entities of E-UTRAN and EPC, as a reference point. Thefollowing Table 1 summarizes reference points illustrated in FIG. 4 . Inaddition to the example of Table 1, various reference points can existdepending on the network structure.

TABLE 1 Reference Point Description S1-MME Reference point for thecontrol plane protocol between E-UTRAN and MME S1-U Reference pointbetween E-UTRAN and Serving GW for the per bearer user plane tunnelingand inter eNodeB path switching during handover S3 It enables user andbearer information exchange for inter 3GPP access network mobility inidle and/or active state. This reference point can be used intra-PLMN orinter-PLMN (e.g. in the case of Inter-PLMN HO). S4 It provides relatedcontrol and mobility support between GPRS Core and the 3GPP Anchorfunction of Serving GW. In addition, if Direct Tunnel is notestablished, it provides the user plane tunneling. S5 It provides userplane tunneling and tunnel management between Serving GW and PDN GW. Itis used for Serving GW relocation due to UE mobility and if the ServingGW needs to connect to a non- collocated PDN GW for the required PDNconnectivity. S11 Reference point for the control plane protocol betweenMME and SGW SGi It is the reference point between the PDN GW and thepacket data network. Packet data network may be an operator externalpublic or private packet data network or an intra operator packet datanetwork, e.g. for provision of IMS services. This reference pointcorresponds to Gi for 3GPP accesses.

Among the reference points illustrated in FIG. 4 , S2a and S2bcorrespond to non-3GPP interfaces. S2a is a reference point to provide auser plane with related control and mobility support between the trustednon-3GPP access and the PDN GW. S2b is a reference point to provide auser plane with related control and mobility support between the ePDGand the PDN GW.

FIG. 5 illustrates an example of a network structure of an evolveduniversal terrestrial radio access network (E-UTRAN) to which thepresent disclosure is applicable.

An E-UTRAN system is an evolved version of the existing UTRAN system andmay be, for example, 3GPP LTE/LTE-A system. Communication networks arewidely deployed to provide various communication services such as voice(e.g., voice over Internet protocol (VoIP)) through IMS and packet data.

Referring to FIG. 5 , an E-UMTS network includes an E-UTRAN, an EPC, andone or more UEs. The E-UTRAN consists of eNBs that provide control planeand user plane protocols to the UE, and the eNBs are interconnected witheach other by means of the X2 interface.

X2 user plane (X2-U) interface is defined between the eNBs. The X2-Uinterface provides non-guaranteed delivery of a user plane packet dataunit (PDU). X2 control plane (X2-CP) interface is defined between twoneighboring eNBs. The X2-CP performs functions of context deliverybetween the eNBs, control of user plane tunnel between a source eNB anda target eNB, delivery of handover-related messages, uplink loadmanagement, and the like.

The eNB is connected to the UE via a radio interface and is connected toan evolved packet core (EPC) by means of the S1 interface.

S1 user plane (S1-U) interface is defined between the eNB and a servinggateway (S-GW). S1 control plane interface (S1-MME) is defined betweenthe eNB and a mobility management entity (MME). The S1 interfaceperforms functions of evolved packet system (EPS) bearer servicemanagement, non-access stratum (NAS) signaling transport, networksharing, MME load balancing, and so on. The S1 interface supportsmany-to-many-relation between the eNB and the MME/S-GW.

The MME can perform various functions such as NAS signaling security,access stratum (AS) security control, inter-core network (CN) nodesignaling for supporting mobility between 3GPP access networks, idlemode UE reachability (including control and execution of pagingretransmission), tracking area identity (TAI) management (for UE in idleand active modes), PDN GW and SGW selection, MME selection for handoverwith MME change, SGSN selection for handover to 2G or 3G 3GPP accessnetworks, roaming, authentication, bearer management functions includingdedicated bearer establishment, support of public warning system (PWS)(including earthquake and tsunami warning system (ETWS) and commercialmobile alert system (CMAS)) message transmission, and the like.

FIG. 6 illustrates an example of a general architecture of E-UTRAN andEPC.

As illustrated in FIG. 6 , the eNB can perform functions such as routingto gateway while radio resource control (RRC) connection is activated,scheduling and transmission of paging messages, scheduling andtransmission of a broadcast channel (BCH), dynamic allocation ofresources in uplink and downlink to the UE, configuration and provisionfor the measurement of the eNB, radio bearer control, radio admissioncontrol, and connection mobility control. The eNB can perform functionssuch as paging generation in the EPC, management of an LTE_IDLE state,ciphering of a user plane, SAE bearer control, and ciphering andintegrity protection of NAS signaling.

Annex J of 3GPP TR 23.799 shows various architectures by combining 5Gand 4G. An architecture using NR and NGC is disclosed in 3GPP TS 23.501.

FIG. 7 illustrates an example of a structure of a radio interfaceprotocol in a control plane between a UE and eNB. FIG. 8 illustrates anexample of a structure of a radio interface protocol in a user planebetween a UE and eNB.

The radio interface protocol is based on 3GPP radio access networkstandard. The radio interface protocol horizontally consists of aphysical layer, a data link layer, and a network layer, and isvertically divided into a user plane for data information transmissionand a control plane for control signaling delivery.

The protocol layers may be divided into L1 (first layer), L2 (secondlayer), and L3 (third layer) based upon three lower layers of an opensystem interconnection (OSI) standard model that is well known in theart of communication systems.

The layers of the radio protocol in the control plane illustrated inFIG. 7 and the layers of the radio protocol in the user planeillustrated in FIG. 8 are described below.

The physical layer, the first layer, provides an information transferservice using a physical channel. The physical layer is connected with amedium access control (MAC) layer located at a higher level via atransport channel, and data between the MAC layer and the physical layeris transferred via the transport channel. Data is transferred betweendifferent physical layers, i.e., between physical layers of atransmission side and a reception side via the physical channel.

The physical channel consists of several subframes on a time axis andseveral subcarriers on a frequency axis. Here, one subframe consists ofa plurality of OFDM symbols and a plurality of subcarriers on the timeaxis. One subframe consists of a plurality of resource blocks, and oneresource block consists of a plurality of OFDM symbols and a pluralityof subcarriers. A unit time, a transmission time interval (TTI), atwhich data is transmitted is 1 ms corresponding to one subframe.

Physical channels existing in the physical layers of the transmissionside and the reception side may be divided into a physical downlinkshared channel (PDSCH) and a physical uplink shared channel (PUSCH) thatare data channels, and a physical downlink control channel (PDCCH), aphysical control format indicator channel (PCFICH), a physicalhybrid-ARQ indicator channel (PHICH), and a physical uplink controlchannel (PUCCH) that are control channels, according to 3GPP LTE.

There are several layers in the second layer. A medium access control(MAC) layer of the second layer functions to map various logicalchannels to various transfer channels, and also performs a function oflogical channel multiplexing for mapping several logical channels to onetransfer channel. The MAC layer is connected to a radio link control(RLC) layer, that is an upper layer, via the logical channel. Thelogical channel is roughly divided into a control channel used totransmit information of the control plane and a traffic channel used totransmit information of the user plane according to a type oftransmitted information.

The MAC layer of the second layer segments and concatenate data receivedfrom the upper layer and adjusts a data size so that a lower layer isadapted to transmit data to a radio section.

A packet data convergence protocol (PDCP) layer of the second layerperforms a header compression function of reducing an IP packet headersize that has a relatively large size and contains unnecessary controlinformation, in order to efficiently transmit data in a radio sectionhaving a small bandwidth upon transmission of IP packet such as IPv4 orIPv6. In the LTE system, the PDCP layer also performs a securityfunction, which consists of ciphering for preventing data interceptionby a third party and integrity protection for preventing datamanipulation by a third party.

A radio resource control (RRC) layer located at the uppermost part ofthe third layer is defined only in the control plane and is responsiblefor controlling logical channels, transport channels, and physicalchannels in relation to configuration, re-configuration, and release ofradio bearers (RBs). The RB means services provided by the second layerto ensure data transfer between the UE and the E-UTRAN.

If an RRC connection is established between an RRC layer of the UE andan RRC layer of a wireless network, the UE is in an RRC connected mode.Otherwise, the UE is in an RRC idle mode.

An RRC state of the UE and an RRC connection method are described below.The RRC state refers to a state in which the RRC of the UE is or is notlogically connected with the RRC of the E-UTRAN. The RRC state of the UEhaving logical connection with the RRC of the E-UTRAN is referred to asan RRC_CONNECTED state, and the RRC state of the UE not having logicalconnection with the RRC of the E-UTRAN is referred to as an RRC_IDLEstate. Since the UE in the RRC_CONNECTED state has the RRC connection,the E-UTRAN can identify the presence of the corresponding UE on a percell basis and thus efficiently control the UE. On the other hand, theE-UTRAN cannot identify the presence of the UE of the RRC_IDLE state,and the UE in the RRC_IDLE state is managed by a core network based on atracking area (TA) which is an area unit larger than the cell. That is,for the UE in the RRC_IDLE state, only presence or absence of thecorresponding UE is identified in an area unit larger than the cell. Inorder for the UE of the RRC_IDLE state to receive typical mobilecommunication services such as voice and data, the UE should transitionto the RRC_CONNECTED state. Each TA is distinguished from another TA bya tracking area identity (TAI) thereof. The UE may configure the TAIthrough a tracking area code (TAC) which is information broadcasted froma cell.

When the user initially turns on the UE, the UE first searches for aproper cell, and then establishes RRC connection in the correspondingcell and registers information of the UE in the core network.Thereafter, the UE stays in the RRC_IDLE state. The UE staying in theRRC_IDLE state (re)selects a cell and checks system information orpaging information, if necessary. This operation is called camping on acell. Only when the UE staying in the RRC_IDLE state needs to establishthe RRC connection, the UE establishes the RRC connection with the RRClayer of the E-UTRAN through a RRC connection procedure and transitionsto the RRC_CONNECTED state. There are several cases where the UEremaining in the RRC_IDLE state needs to establish the RRC connection.For example, the cases may include an attempt of a user to make a phonecall, an attempt to transmit data, or transmission of a response messagewhen receiving a paging message from the E-UTRAN.

A non-access stratum (NAS) layer positioned over the RRC layer performsfunctions such as session management and mobility management.

The NAS layer illustrated in FIG. 7 is described in detail below.

The evolved session management (ESM) belonging to the NAS layer performsfunctions such as default bearer management and dedicated bearermanagement, and is responsible for controlling the UE to use a PSservice from a network. The default bearer resources are allocated froma network when they are accessed to the network upon first access to aspecific packet data network (PDN). In this instance, the networkallocates an IP address available for the UE so that the UE can use adata service, and also allocates QoS of a default bearer. LTE roughlysupports two types of bearers including a bearer with guaranteed bitrate (GBR) QoS characteristics for guaranteeing a specific bandwidth fordata transmission/reception and a non-GBR bearer with best effort QoScharacteristics without guaranteeing a bandwidth. The default bearer isallocated the non-GBR bearer. The dedicated bearer may be allocated abearer with GBR or non-GBR QoS characteristics.

A bearer that the network allocates to the UE is referred to as anevolved packet service (EPS) bearer. When the network allocates the EPSbearer to the UE, the network assigns one ID. This ID is called an EPSbearer ID. One EPS bearer has QoS characteristics of a maximum bit rate(MBR) and/or a guaranteed bit rate (GBR).

FIG. 9 illustrates a general architecture of NR-RAN.

Referring to FIG. 9 , the NR-RAN node may be one of the followings.

-   -   gNB providing NR user plane and control plane protocols towards        the UE; or    -   ng-eNB providing E-UTRA user plane and control plane protocols        towards the UE.

The gNB and the ng-eNB are interconnected with each other by means ofthe Xn interface. The gNB and ng-eNB are also interconnected with theaccess and mobility management function (AMF) by means of the NGinterface to SGC, more specifically, by means of the NG-C interface, andare interconnected with the user plane function (UPF) by means of theNG-U interface (see 3GPP TS 23.501 [3]).

For reference, architecture and F1 interface for functional split aredefined in 3GPP TS 38.401 [4].

FIG. 10 illustrates an example of general functional split betweenNG-RAN and SGC.

Referring to FIG. 10 , yellow boxes depict logical nodes, and whiteboxes depict main functions.

The gNB and ng-eNB host the following functions.

-   -   Functions for Radio Resource Management: radio bearer control,        radio admission control, connection mobility control, and        dynamic allocation of resources to UEs in both uplink and        downlink (scheduling);    -   IP header compression, encryption and integrity protection of        data;    -   Selection of an AMF at IMT-2000 3GPP-UE attachment when no        routing to an AMF can be determined from the information        provided by the UE;    -   Routing of user plane data towards UPF(s);    -   Routing of control plane information towards AMF;    -   Connection setup and release;    -   Scheduling and transmission of paging messages;    -   Scheduling and transmission of system broadcast information        (originated from the AMF or OAM);    -   Measurement and measurement reporting configuration for mobility        and scheduling;    -   Transport level packet marking in the uplink;    -   Session management;    -   Support of network slicing;    -   QoS flow management and mapping to data radio bearers;    -   Support of UEs in RRC_INACTIVE state;    -   Distribution function for NAS messages;    -   Radio access network sharing;    -   Dual connectivity;    -   Tight interworking between NR and E-UTRA.

The AMF hosts the following main functions (see 3GPP TS 23.501 [3]).

-   -   NAS signalling termination;    -   NAS signalling security;    -   AS security control;    -   Inter CN node signalling for mobility between 3GPP access        networks;    -   Idle mode UE reachability (including control and execution of        paging retransmission);    -   Registration area management;    -   Support of intra-system and inter-system mobility;    -   Access authentication;    -   Access authorization including check of roaming rights;    -   Mobility management control (subscription and policies);    -   Support of network slicing;    -   SMF selection.

The UPF hosts the following main functions (see 3GPP TS 23.501 [3]).

-   -   Anchor point for intra-/inter-RAT mobility (when applicable);    -   External PDU session point of interconnect to data network;    -   Packet routing and forwarding;    -   Packet inspection and user plane part of policy rule        enforcement;    -   Traffic usage reporting;    -   Uplink classifier to support routing traffic flows to a data        network;    -   Branching point to support multi-homed PDU session;    -   QoS handling for user plane (e.g., packet filtering, gating,        UL/DL rate enforcement);    -   Uplink traffic verification (SDF to QoS flow mapping);    -   Downlink packet buffering and downlink data notification        triggering.

The session management function (SMF) hosts the following main functions(see 3GPP TS 23.501 [3]).

-   -   Session management;    -   UE IP address allocation and management;    -   Selection and control of UP function;    -   Configure traffic steering at UPF to route traffic to proper        destination;    -   Control part of policy enforcement and QoS;    -   Downlink data notification.

FIG. 11 illustrates an example of a general architecture of 5G.

The following is given a description for each reference interface andeach node illustrated in FIG. 11 .

An access and mobility management function (AMF) supports functions ofinter-CN node signaling for mobility between 3GPP access networks,termination of radio access network (RAN) CP interface (N2), terminationof NAS signaling (N1), registration management (registration areamanagement), idle mode UE reachability, support of network slicing, SMFselection, and the like.

Some or all of the functions of the AMF can be supported in a singleinstance of one AMF.

A data network (DN) means, for example, operator services, internetaccess, or 3rd party service, etc. The DN transmits a downlink protocoldata unit (PDU) to the UPF or receives the PDU transmitted from the UEfrom the UPF.

A policy control function (PCF) receives information about packet flowfrom an application server and provides functions of determiningpolicies such as mobility management and session management.

A session management function (SMF) provides a session managementfunction. If the UE has a plurality of sessions, the sessions can berespectively managed by different SMFs.

Some or all of the functions of the SMF can be supported in a singleinstance of one SMF.

A unified data management (UDM) stores subscription data of user, policydata, etc.

A user plane function (UPF) transmits the downlink PDU received from theDN to the UE via the (R)AN and transmits the uplink PDU received fromthe UE to the DN via the (R)AN.

An application function (AF) interacts with 3GPP core network to provideservices (e.g., to support functions of an application influence ontraffic routing, network capability exposure access, interaction withpolicy framework for policy control, and the like).

A (radio) access network (R)AN collectively refers to a new radio accessnetwork supporting both evolved E-UTRA, that is an evolved version of 4Gradio access technology, and a new radio (NR) access technology (e.g.,gNB).

The gNB supports functions for radio resource management (i.e., radiobearer control, radio admission control, connection mobility control,and dynamic allocation of resources to UEs in uplink/downlink (i.e.,scheduling)).

The UE means a user equipment.

In the 3GPP system, a conceptual link connecting between the NFs in the5G system is defined as a reference point.

N1 is a reference point between the UE and the AMF, N2 is a referencepoint between the (R)AN and the AMF, N3 is a reference point between the(R)AN and the UPF, N4 is a reference point between the SMF and the UPF,N6 is a reference point between the UPF and the data network, N9 is areference point between two core UPFs, N5 is a reference point betweenthe PCF and the AF, N7 is a reference point between the SMF and the PCF,N24 is a reference point between the PCF in the visited network and thePCF in the home network, N8 is a reference point between the UDM and theAMF, N10 is a reference point between the UDM and the SMF, N11 is areference point between the AMF and the SMF, N12 is a reference pointbetween the AMF and an authentication server function (AUSF), N13 is areference point between the UDM and the AUSF, N14 is a reference pointbetween two AMFs, N15 is a reference point between the PCF and the AMFin case of non-roaming scenario and a reference point between the PCF inthe visited network and the AMF in case of roaming scenario, N16 is areference point between two SMFs (reference point between the SMF in thevisited network and the SMF in the home network in case of roamingscenario), N17 is a reference point between AMF and 5G-equipmentidentity register (EIR), N18 is a reference point between the AMF and anunstructured data storage function (UDSF), N22 is a reference pointbetween the AMF and a network slice selection function (NSSF), N23 is areference point between the PCF and a network data analytics function(NWDAF), N24 is a reference point between the NSSF and the NWDAF, N27 isa reference point between a network repository function (NRF) in thevisited network and the NRF in the home network, N31 is a referencepoint between NSSF in the visited network and NSSF in the home network,N32 is a reference point between security protection proxy (SEPP) in thevisited network and SEPP in the home network, N33 is a reference pointbetween a network exposure function (NEF) and the AF, N40 is a referencepoint between the SMF and a charging function (CHF), and N50 is areference point between the AMF and a circuit bearer control function(CBCF).

FIG. 11 illustrates a reference model where the UE accesses to one DNusing one PDU session, by way of example, for convenience ofexplanation, but the present invention is not limited thereto.

The following has been described based on the EPS system using the eNBfor convenience of explanation. However, the EPS system may be replacedwith the 5G system by replacing the eNB by the gNB, the mobilitymanagement (MM) function of the MME by the AMF, the SM function ofS/P-GW by the SMF, and the user plane-related function of the S/P-GW bythe UPF.

In the above, the present disclosure has been described based on theEPS, but the corresponding content can be supported by going throughsimilar operations through processes/messages/information for similarpurpose in the 5G system.

PLMN Selection Procedure

The following Table 2 is content related to a PLMN selection defined in3GPP TS 22.011.

TABLE 2 The UE shall select and attempt registration on other PLMNs, ifavailable and allowable, if the location area is not in the list of“forbidden LAs for roaming” and the tracking area is not in the list of“forbidden TAs for roaming” (see 3GPP TS 23.122 [3]), in the followingorder: i) An EHPLMN if the EHPLMN list is present or the HPLMN (derivedfrom the IMSI) if the EHPLMN list is not present for preferred accesstechnologies in the order specified. In the case that there are multipleEHPLMNs present then the highest priority EHPLMN shall be selected. Itshall be possible to configure a voice capable UE so that it shall notattempt registration on a PLMN if all cells identified as belonging tothe PLMN do not support the corresponding voice service. ii) Each entryin the “User Controlled PLMN Selector with Access Technology” data fieldin the SIM/USIM (in priority order). It shall be possible to configure avoice capable UE so that it shall not attempt registration on a PLMN ifall cells identified as belonging to the PLMN do not support thecorresponding voice service. iii) Each entry in the “Operator ControlledPLMN Selector with Access Technology” data field in the SIM/USIM (inpriority order). It shall be possible to configure a voice capable UE sothat it shall not attempt registration on a PLMN if all cells identifiedas belonging to the PLMN do not support the corresponding voice service.iv) Other PLMN/access technology combinations with sufficient receivedsignal quality (see 3GPP TS 23.122 [3]) in random order. It shall bepossible to configure a voice capable UE so that it shall not attemptregistration on a PLMN if all cells identified as belonging to the PLMNdo not support the corresponding voice service. v) All other PLMN/accesstechnology combinations in order of decreasing signal quality. It shallbe possible to configure a voice capable UE so that it shall not attemptregistration on a PLMN if all cells identified as belonging to the PLMNdo not support the corresponding voice service. In the case of a UEoperating in UE operation mode A or B, an allowable PLMN is one which isnot in the “Forbidden PLMN” data field in the SIM/USIM. This data fieldmay be extended in the ME memory (see clause 3.2.2.4). In the case of aUE operating in UE operation mode C, an allowable PLMN is one which isnot in the “Forbidden PLMN” data field in the SIM/USIM or in the list of“forbidden PLMNs for GPRS service” in the ME. If successful registrationis achieved, the UE shall indicate the selected PLMN.

Roaming Steering

The following Table 3 represents a method of affecting the PLMNselection in relation to the registration, and is described in TS22.011.

TABLE 3 Steering to a specific VPLMN It shall be possible for the HPLMNat any time to direct a UE, that is in automatic mode, to search for aspecific VPLMN and, if it is available, move to that VPLMN as soon aspossible. This VPLMN shall then be regarded as the highest priorityVPLMN as defined by the operator, though any EHPLMN or PLMN on the UserControlled PLMN list shall have higher priority. This process shall bedone transparently and without inconvenience to the user. If the UE isin manual mode, the steering request shall be ignored. If the UE isregistered on a VPLMN that is present on the User Controlled PLMN List,the steering request shall be ignored. PLMNs contained on the UserControlled PLMN List shall have priority over the steered-to-PLMN. TheUE shall attempt to register on the specified VPLMN even if thespecified VPLMN is present on a Forbidden List. This mechanism shall beavailable to the HPLMN even if the VPLMN the UE is registered on iscompliant to an earlier release of the 3GPP specifications. VPLMNRedirection It shall be possible for the HPLMN to request a UE, that isin automatic mode, to find and register on a different VPLMN from theone it is currently using or trying to register on, if another VPLMN,that is not in a Forbidden List, is available. The original VPLMN shallthen be treated as the lowest priority VPLMN and would not be selectedby the UE unless it is the only one available to the UE or has beenselected in manual mode. This process shall be done transparently andwithout inconvenience to the user. If the UE is in manual mode, theredirection request shall be ignored. If the UE is registered on a VPLMNthat is present on the User Controlled PLMN List, the redirectionrequest shall be ignored. This mechanism shall be available to the HPLMNeven if the VPLMN the UE is registered on is compliant to an earlierrelease of the 3GPP specifications.

Embodiments of the Present Disclosure

As the mobile communication services have become an indispensableservice in daily life, each mobile service provider is making variousattempts to prevent interruption of services. For example, the mobileservice providers use a plurality of wired networks in a core networkduration in a wireless network or install a plurality of core networkssuch as AMFs/MMEs, and thus can prevent interruption of communicationservices by performing backup in other network node even if there is aproblem in one network node.

However, in the event of a disaster such as a fire or an earthquake, theabove measures may not be helpful. For example, this is because, in theevent of a fire, all communication cables connected to the outside fromone node of the wireless network may be lost. For example, in avirtualized cloud environment, the plurality of core networks such asAMFs/MMEs are highly likely to be implemented in one data center locatedin the same area. In addition, if the data center is located at acentral point of the earthquake, there is a high possibility that allfunctions will be lost no matter how the plurality of AMFs/MMEs areimplemented.

Accordingly, the most efficient way is to think of roaming. That is, ifthe UE cannot receive communication service since there is a problem ina network of a mobile service provider to which the UE subscribes, theUE can roam to other surrounding mobile service provider and receivecommunication service. Each mobile service provider installs wirelessnetworks and core networks in its licensed area, installs them in adifferent building, and builds networks in a different way. Hence, thedisasters listed as examples in the preceding description may not havethe same impact on all the mobile service providers.

Each mobile service provider actively installs wireless networks andcore networks in an area where he/she obtained a license from an actuallegal institution and obtained a business right. However, the providercannot install the wireless/core networks in other areas because thereis no business right. For example, if any UE leaves an area or a countryto which it subscribes, the UE receives a roaming service over a networkof other service providers. However, if the UE is located in the area orcountry to which it subscribes, the UE cannot receive the roamingservice in the area due to a relationship between the mobile serviceproviders competing with each other.

In particular, in the case of a roaming service in an overseas area,when the UE is turned on in a new area, the UE automatically activatesthe roaming service since the UE cannot discover the network of themobile service provider to which the UE subscribes. However, if the UEis located in an area where its provider mainly conducts business, theUE does not activate the roaming service and thus cannot receive theroaming service in the disaster situation as described above.

In particular, depending on the reason why the mobile service provider,to which the UE subscribes, cannot provide the communication services, aservice interruption time for which actual service is not provided tothe UE may vary variously. For example, when the power supply to awireless network is interrupted, the wireless network does not generateany radio waves. Therefore, the UE can recognize a problem of itssubscribed network by detecting a radio wave reception failure. However,if wired communication lines of a wireless network and a core networkare cut off, the wireless network still generates radio waves.Therefore, it is highly likely that the UE will recognize that thecommunication network is still alive and will not take any action. Ifsomeone attempts to make a call to the UE, the UE may not recognize it.

Accordingly, the present disclosure provides a method, in which when anyUE cannot receive communication services from a communication networksince a problem occurs in the communication network connected to the UE,interruption of communication services is minimized by efficientlymoving the UE to other communication network.

To this end, first, in the present disclosure, in order to allow a UE torapidly recognize a problem of communication service, if a wirelessnetwork cannot smoothly provide communication services to UEs within anarea managed by the wireless network, the wireless network can informthe UE of it.

Through this, after the UE is informed that the UE cannot receive thecommunication services from a communication network to which the UEitself currently accesses or registers, the UE newly performs a PLMNselection procedure to select other communication network not thecurrently registered network, and performs a registration process withrespect to the selected communication network.

FIG. 12 is a flow chart illustrating an example of selecting a PLMNaccording to an embodiment of the present disclosure.

As illustrated in FIG. 12 , a UE 1210 may perform a registration to afirst PLMN (CN 1) 1213 via a first base station (RAN 1) 1211, in 51201.

For example, the UE may find a HPLMN, to which the UE is subscribed, andselect its PLMN to perform a registration process. Afterwards, the UEmay be placed in an idle mode and placed in a connected mode based on anactivation state of a traffic.

Subsequently, the first base station may transmit a heartbeat protocolto the first PLMN, in S1203.

Next, the first base station may detect a failure of the first PLMN, inS1205.

For example, the first base station may find a problem in a first systemincluding the first base station and the first PLMN. The first basestation may recognize that the first system cannot provide communicationservices to the UE (user).

Specifically, the first base station may inform the UE about whetherthere is a failure of the first PLMN, S1207.

For example, the first base station may send a message, which informsthat the first system cannot normally provide services to the UEs(users), to the UEs receiving services from the first system. Here, theUE may recognize, based on the message received from the first basestation, that the UE cannot receive normally the communication servicesfrom the first PLMN to which the UE is registered, and may perform thePLMN selection procedure.

Subsequently, the UE may select a new PLMN and perform the campingand/or registration process on the selected second PLMN, in 51209.

Method 1

In the process illustrated in FIG. 12 , a method for the first basestation (first wireless network) to recognize a failure problem of thefirst PLMN (first core network) may use PFCP HearBeat protocol, etc.specified in the standard document TS 23.527. That is, the first basestation (e.g., gNB or eNB) periodically exchanges a packet withUPF/AMF/MME/S-GW, etc. that have been connected to the first basestation, and decides that a problem has occurred in the first PLMN(first core network) when there is no packet that has been exchanged fora predetermined time.

Method 2

A plurality of UEs may be present/connected in a cell in which one basestation is included, and the respective UEs are placed in various statesincluding RRC Connected, RRC Connected inactive, RRC Idle, etc.depending on each data generation state or voice call progress state,etc. Based on the UE's state, the UE may immediately exchangeinformation with the base station, and exchange information with thebase station at a specific time. If the base station, i.e., the wirelessnetwork recognizes a problem occurring in the core wireless network(PLMN), it is important that the base station quickly informs the UE ofthe problem, while at the same time transmitting this information mostefficiently.

Method 2-1

As a method for the first base station (wireless network) to efficientlyinform each UE of a problem in a current communication network and alloweach UE to move to another network, a system information block (SIB) maybe used.

If the connection between the first base station and the first PLMN isreleased, MBMS method cannot be used since the first base station cannotproduce contents of MBMS. In this case, the first base station (wirelessnetwork) may perform an operation such as paging to inform the UE of anupdate of SIB information, and then may inform the UE of the problemoccurring in the first PLMN via the SIB information or indicate to theUE the movement to another PLMN.

FIG. 13 is a flow chart illustrating a PLMN selection procedureaccording to method 2-1.

As illustrated in FIG. 13 , a first base station may detect a failure ofa first PLMN, in S1301.

The first base station may send an SIB update notification message to aUE, in 51303.

The UE may check (monitor) whether there is paging information (ormessage) that the UE shall receive during a predetermined receptionduration (time duration configured to attempt reception from the firstbase station), in 51305. If the paging information to be received is notmonitored, the UE may maintain the existing operation.

Subsequently, if the first base station detects the failure of the firstPLMN and cannot provide communication services to the UE, and thus theUE needs to move to other system, the first base station may inform theUE of it through an updated SIB message, in 51307.

The UE may receive (monitor) the SIB according to a predetermined SIBtransmission periodicity, S1309.

The UE may determine a switch to other PLMN (network) as indicated inthe SIB message, S1311.

Subsequently, the UE may select a new PLMN (network) and request campingand/or registration to the selected new PLMN (core network 2), in S1313.

For example, the SIB may contain the following content.

SIB1 contains information relevant when evaluating if a UE is allowed toaccess a cell, and defines the scheduling of other system information.It also contains radio resource configuration information that is commonfor all UEs and barring information applied to the unified accesscontrol.

The content of a SIB1 message is as follows.

Signalling radio bearer: N/A

RLC-SAP: TM

Logical channel: BCCH

Direction: Network to UE

Table 4 is an example of the SIB1 message.

TABLE 4 -- ASN1START -- TAG-SIB1-START SIB1 ::= SEQUENCE { cellSelectionInfo SEQUENCE {   q-RxLevMin    Q-RxLevMin,  q-RxLevMinOffset      INTEGER        (1 .. 8) OPTIONAL,  -- Need R  q-RxLevMinSUL               Q-RxLevMin OPTIONAL,  -- Need R  q-QualMin                Q-QualMin OPTIONAL,  -- Need R  q-QualMinOffset            INTEGER  (1 .. 8) OPTIONAL  -- Need R  }OPTIONAL,  -- Need S  cellAccessRelatedInfo CellAccessRelatedInfo, connEstFailureControl          ConnEstFailureControl OPTIONAL,  -- NeedR  si-SchedulingInfo            SI-SchedulingInfo OPTIONAL,  -- Need R servingCellConfigCommon      ServingCellConfigCommonSIB OPTIONAL,  --Need R  ims-Emergency Support        ENUMERATED  {true} OPTIONAL,  --Need R  eCallOverIMS-Support        ENUMERATED  {true} OPTIONAL,  --Cond Absent  ue-Timers AndConstants        UE-Timers AndConstantsOPTIONAL,  -- Need R  uac-BarringInfo  SEQUENCE {   uac-BarringForCommon        UAC-BarringPerCatList OPTIONAL,  -- Need S  uac-BarringPerPLMN-List       UAC-BarringPerPLMN-List OPTIONAL,  --Need S   uac-BarringInfoSetList   UAC-BarringInfoSetList,  uac-AccessCategory 1-Selection AssistanceInfo CHOICE {    plmnCommon        UAC-AccessCategory 1- SelectionAssistanceInfo,   individualPLMNList           SEQUENCE (SIZE (2 .. maxPLMN)) OFUAC-AccessCategory 1-SelectionAssistanceInfo   } OPTIONAL  } OPTIONAL, -- Need R  useFullResumeID        ENUMERATED  {true} OPTIONAL,  -- NeedN SelectOtherPLMN             Boolean  lateNonCriticalExtension          OCTET  STRING OPTIONAL,  nonCriticalExtension             SEQUENCE{ } OPTIONAL } UAC-AccessCategory 1-SelectionAssistanceInfo ::=     ENUMERATED {a, b, c} -- TAG-SIB1-STOP -- ASN1STOP

Table 5 is an example of SIB1 field descriptions.

TABLE 5 SIB1 field descriptions q-QualMin Parameter “Q_(qualmin)” in TS38.304 [20], applicable for serving cell. If the field is not present,the UE applies the (default) value of negative infinity for Q_(qualmin).q-QualMinOffset Parameter “Q_(qualminoffset)” in TS 38.304 [20]. Actualvalue Q_(qualminoffset) = field value [dB]. If cellSelectionInfo is notpresent or the field is not present, the UE applies the (default) valueof 0 dB for Q_(qualminoffset). Affects the minimum required qualitylevel in the cell. q-RxLevMin Parameter “Q_(rxlevmin)” in TS 38.304[20], applicable for serving cell. q-RxLevMinOffset Parameter“Q_(rxlevminoffset)” in TS 38.304 [20]. Actual value Q_(rxlevminoffset)= field value * 2 [dB]. If absent, the UE applies the (default) value of0 dB for Q_(rxlevminoffset). Affects the minimum required Rx level inthe cell. q-RxLevMinSUL Parameter “Q_(rxlevminSUL)” in TS 38.304 [4],applicable for serving cell uac-BarringForCommon Common access controlparameters for each access category. Common values are used for allPLMNs, unless overwritten by the PLMN specific configuration provided inuac- BarringPerPLMN-List. The parameters are specified by providing anindex to the set of configurations (uac-BarringInfoSetList). UEbehaviour upon absence of this field is specified in section 5.3.14.2.useFullResumeID Indicates which resume identifier and Resume requestmessage should be used. UE uses full I-RNTI and RRCResumeRequest1 if thefield is present, or short I-RNTI and RRCResumeRequest if the field isabsent. uac-AccessCategory 1-SelectionAssistanceInfo Information used todetermine whether Access Category 1 applies to the UE, as defined in[25]. A UE compliant with this version of the specification shall ignorethis field. selectotherPLMN Indicates whether the UE should select otherPLMN. This information can further include PLMN ID of candidate PLMN.

Table 6 represents an explanation of SIB1 field.

TABLE 6 Conditional Presence Explanation Absent The field is not used inthis version of the specification, if received, the UE shall ignore.

That is, the wireless network may transmit, to the UE, information suchas SelectOtherPLMN or information of similar purpose or name, and mayallow the UEs to select other PLMN not a current PLMN. If informationsuch as the SelectOtherPLMN contains the meaning of ‘yes’ or ‘true’, theUE may select other PLMN except the currently selected PLMN and attemptthe registration.

The SelectOtherPLMN information may selectively include a target PLMNID. That is, if pre-designated information exists in the wirelessnetwork, the wireless network may send the UE a message related towhether there is any available surrounding PLMN.

Using this, the UE may first perform selection and registration to thePLMN included therein.

Alternatively, the message may be expressed in various ways, and mayalso be included in other messages, for example, MIB or otherinformation elements. For example, this is the same as the followingTable 5.

-   -   MIB

The MIB includes the system information transmitted on BCH.

Signalling radio bearer: N/A

RLC-SAP: TM

Logical channel: BCCH

Direction: Network to UE

Table 7 is an example of MI message.

TABLE 7 MIB -- ASN1START -- TAG-MIB-START MIB ::= SEQUENCE { systemFrameNumber    BIT STRING (SIZE (6)),  subCarrierSpacingCommon  ENUMERATED {scs15or60, scs30or120},  ssb-SubcarrierOffset INTEGER(0..15),  dmrs-TypeA-Position  ENUMERATED {pos2, pos3}, pdcch-ConfigSIB1   PDCCH-ConfigSIB1,  cellBarred  ENUMERATED {barred,notBarred},  intraFreqReselection ENUMERATED {allowed, notAllowed}, spare   BIT STRING (SIZE (1))  SelectOtherPLMN } -- TAG-MIB-STOP --ASN1STOP

Table 8 is an example of MIB field descriptions.

TABLE 8 MIB field descriptions cellBarred Barred means the cell isbarred, as defined in TS 38.304 [20]. dmrs-TypeA-Position Position of(first) DM-RS for downlink (see 38.211, section 7.4.1.1.1) and uplink(see 38.211, section 6.4.1.1.3). intraFreqReselection Controls cellselection/reselection to intra-frequency cells when the highest rankedcell is barred, or treated as barred by the UE, as specified in TS38.304 [20]. pdcch-ConfigSIB1 See TS 38.213 [13]. Determines a commonControlResourceSet (CORESET) a common search space and necessary PDCCHparameters. If the field ssb-SubcarrierOffset indicates that SIB1 is notpresent, the field pdcch-ConfigSIB1 indicate the frequency positionswhere the UE may find SS/PBCH block with SIB1 or the frequency rangewhere the network does not provide SS/PBCH block with SIB1.ssb-SubcarrierOffset Corresponds to k_(SSB) (see TS 38.213 [13]), whichis the frequency domain offset between SSB and the overall resourceblock grid in number of subcarriers. (See TS 38.211). The value range ofthis field may be extended by an additional most significant bit encodedwithin PBCH as specified in TS 38.213 [13]. This field may indicate thatthis beam does not provide SIB1 and that there is hence no commonCORESET. In this case, the field pdcch-ConfigSIB1 may indicate thefrequency positions where the UE may (not) find a SS/PBCH with a controlresource set and search space for SIB1 (see TS 38.213 [13], section 13).subCarrierSpacingCommon Subcarrier spacing for SIB1, Msg.2/4 for initialaccess and broadcast SI-messages. If the UE acquires this MIB on acarrier frequency < 6 GHz, the value scs15or60 corresponds to 15 Khz andthe value scs30or120 corresponds to 30 KHz. If the UE acquires this MIBon a carrier frequency > 6 GHz, the value scs15or60 corresponds to 60Khz and the value scs30or120 corresponds to 120 kHz. systemFrameNumberThe 6 most significant bit (MSB) of the 10-bit System Frame Number. The4 LSB of the SFN are conveyed in the PBCH transport block as part ofchannel coding (i.e. outside the MIB encoding).

Method 2-1

A method of informing a problem of a current network via SIB or MIB,etc. as above can be applied to a UE that is in an idle mode or an RRCinactive mode. However, a base station may also indicate a UE in an RRCConnected mode to move more rapidly to another PLMN using informationsuch as RRC Release.

-   -   RRCRelease

The RRCRelease message is used to command the release of an RRCconnection or the suspension of the RRC connection.

Signalling radio bearer: SRB1

RLC-SAP: AM

Logical channel: DCCH

Direction: Network to UE

The RRCRelease message is the same as the following Table 9.

TABLE 9 -- ASN1START -- TAG-RRCRELEASE-START RRCRelease ::=     SEQUENCE {  rrc-TransactionIdentifier     RRC-TransactionIdentifier,  criticalExtensions        CHOICE {  rrcRelease               RRCRelease-IEs,   criticalExtensionsFuture           SEQUENCE { }  } } RRCRelease-IEs ::=     SEQUENCE { redirectedCarrierInfo                      RedirectedCarrierInfoOPTIONAL,  -- Need N  SelectOtherPLMN                   SelectOtherPLMN cellReselectionPriorities                    CellReselectionPrioritiesOPTIONAL,  -- Need R  suspendConfig                        SuspendConfigOPTIONAL,  -- Need R  deprioritisationReq        SEQUENCE {  deprioritisationType              ENUMERATED {frequency, nr},  deprioritisationTimer              ENUMERATED {min5, min10, min15,min30}  } OPTIONAL,  -- Need N  lateNonCriticalExtension                      OCTET  STRING OPTIONAL,  nonCriticalExtension                       SEQUENCE{ } OPTIONAL } RedirectedCarrierInfo ::=  CHOICE {  nr             CarrierInfoNR,  eutra           RedirectedCarrierInfo-EUTRA,  ... }RedirectedCarrierInfo-EUTRA ::=    SEQUENCE {  eutraFrequency              ARFCN-ValueEUTRA,  cnType-r15                ENUMERATED{epc,fiveGC} OPTIONAL } CarrierInfoNR ::=    SEQUENCE {  carrierFreq         ARFCN-ValueNR,  ssbSubcarrierSpacing         SubcarrierSpacing, smtc                         SSB-MTC OPTIONAL,   -- Need S  ... }SuspendConfig :=    SEQUENCE {  fullI-RNTI           I-RNTI-Value, shortI-RNTI           ShortI-RNTI-Value,  ran-PagingCycle          PagingCycle,  ran-Notification AreaInfo                RAN-NotificationAreaInfo OPTIONAL,  -- Need M  t380               PeriodicRNAU-TimerValue OPTIONAL,  -- Need R nextHopChainingCount            NextHopChainingCount,  ... }PeriodicRNAU-TimerValue ::=      ENUMERATED { min5, min10, min20, min30,min60, min120, min360, min720} CellReselectionPriorities ::= SEQUENCE { freqPriorityListEUTRA                     FreqPriorityListEUTRAOPTIONAL,    -- Need M  freqPriority ListNR                      FreqPriority ListNR OPTIONAL,    -- Need M  t320            ENUMERATED {min5, min10, min20, min30, min60, min120,min180, spare1}       OPTIONAL,    -- Need R  ... } PagingCycle ::=    ENUMERATED {rf32, rf64, rf128, rf256} FreqPriority ListEUTRA :=            SEQUENCE (SIZE (1..maxFreq)) OF FreqPriorityEUTRAFreqPriorityListNR ::=             SEQUENCE (SIZE (1..maxFreq)) OFFreqPriorityNR FreqPriorityEUTRA :=     SEQUENCE {  carrierFreq          ARFCN-ValueEUTRA,  cellReselectionPriority      CellReselectionPriority,  cellReselectionSubPriority                 CellReselectionSubPriority OPTIONAL    -- Need R }FreqPriority NR ::=     SEQUENCE {  carrierFreq          ARFCN-ValueNR, cellReselectionPriority       CellReselectionPriority, cellReselectionSubPriority                  CellReselectionSubPriorityOPTIONAL    -- Need R } RAN-NotificationAreaInfo ::= CHOICE {  cellList         PLMN-RAN-AreaCellList,  ran-AreaConfigList         PLMN-RAN-AreaConfigList,  ... } PLMN-RAN-AreaCellList ::=      SEQUENCE (SIZE (1..maxPLMNIdentities)) OF PLMN-RAN-AreaCellPLMN-RAN-AreaCell ::=       SEQUENCE {  plmn-Identity                       PLMN-Identity OPTIONAL,  -- Need S  ran-AreaCells               SEQUENCE (SIZE (1..32)) OF CellIdentity }PLMN-RAN-AreaConfigList :=       SEQUENCE (SIZE (1..maxPLMNIdentities))OF PLMN-RAN-AreaConfig PLMN-RAN-AreaConfig :=        SEQUENCE { plmn-Identity                        PLMN-Identity OPTIONAL,  -- Need S ran-Area             SEQUENCE (SIZE (1..16)) OF RAN- AreaConfig }RAN-AreaConfig :=       SEQUENCE {  trackingAreaCode  TrackingAreaCode, ran-AreaCodeList   SEQUENCE (SIZE (1..32)) OF RAN-AreaCode OPTIONAL  -- Need R } -- TAG-RRCRELEASE-STOP -- ASN1STOP

Here, FFS Whether RejectWaitTimer is included in the RRCRelease message.

Table 10 is an example of RRCRelease field descriptions.

TABLE 10 RRCRelease field descriptions cnType Indicate that the UE isredirected to EPC or 5GC. deprioritisationReq Indicates whether thecurrent frequency or RAT is to be de-prioritised. The UE shall be ableto store a deprioritisation request for up to X frequencies (applicablewhen receiving another frequency specific deprioritisation requestbefore T325 expiry). deprioritisationTimer Indicates the period forwhich either the current carrier frequency or NR is deprioritised. ValueminN corresponds to N minutes. suspendConfig Indicates configuration forthe RRC_INACTIVE state. t380 Refers to the timer that triggers theperiodic RNAU procedure in UE. Value min5 corresponds to 5 minutes,value min10 corresponds to 10 minutes and so on. ran-PagingCycle Refersto the UE specific cycle for RAN-initiated paging. Value rf32corresponds to 32 radio frames, rf64 corresponds to 64 radio frames andso on. redirectedCarrierInfo Indicates a carrier frequency (downlink forFDD) and is used to redirect the UE to an NR or an inter-RAT carrierfrequency, by means of the cell selection upon leaving RRC_CONNECTED(see TS 38.304 [20]) selectotherPLMN Indicates whether the UE shouldselect other PLMN. This information can further include PLMN ID ofcandidate PLMN.

That is, the UE receiving the message as specified above performs newlya PLMN selection procedure, and selects another PLMN except a currentPLMN in this procedure to perform the registration.

Method 3

In the above procedure, a UE, that is indicated to select other networknot a current network (PLMN) from a cell (base station) on which the UEcurrently camps or is connected, performs the PLMN selection procedure,and a network (first PLMN) that the UE currently accesses in thisprocedure is excluded from candidates. For example, the UE includes anetwork, that transmits information to select the network that the UEcurrently accesses or other network, in a forbidden PLMN list.

Method 4

In general, in an area where a service provider, to which any UEsubscribes services, is located, a network of the service provider is incompetition with a network of other service provider. That is, whenthere are MNO A and MNO B in any area, if any UE has subscribed to theMNO A, the MNO B will not allow the access of the UE since the UEbelongs to a network of the MNO A that is a competitor. This is adifferent situation from international roaming. This is because the MNOA does not own a network abroad, and thus overseas MNO is a cooperativepartner for the MNO A.

Accordingly, when the UE needs to move to a network of other competitorsdue to a problem in a network of a provider to which the UE subscribesas above, the base station shall inform the UE so that the network ofother competitors does not reject a registration of the UE. That is, amethod is necessary to reject an access in a general situation not adisaster situation and to allow a registration in the event of an accessof the disaster situation.

Accordingly, the present disclosure proposes that a UE informs aregistration due to its disaster situation when the UE accesses awireless network or a core network, in order to achieve the objectsdescribed above.

FIG. 14 is a flow chart illustrating a PLMN selection procedureaccording to method 4.

As illustrated in FIG. 14 , a UE may select a core network 2 (secondPLMN) based on an indication of the first base station in FIGS. 12 and13 , in S1401.

Next, the UE may send a RRC connection request to the selected corenetwork 2 (second PLMN), in S1403. In this process, the UE may informattempting to access the second PLMN based on a problem such as a homenetwork of the UE or an indication in a previous network. That is, theUE may include, in an access request message, the fact that a cause ofthe access request is disaster roaming, while sending the access requestmessage to the second PLMN.

Next, the UE may perform a registration to the core network 2 based onthe RRC connection established in step S1403, in S1405.

For example, the RRC message and the NAS message may be exemplified asfollows.

RRCSetupRequest

The RRCSetupRequest message is used to request the establishment of anRRC connection.

Signalling radio bearer: SRB0

RLC-SAP: TM

Logical channel: CCCH

Direction: UE to Network

Table 11 is an example of the RRCSetupRequest message.

TABLE 11 RRCSetupRequest message -- ASN1START --TAG-RRCSETUPREQUEST-START RRCSetupRequest ::=    SEQUENCE { rrcSetupRequest      RRCSetupRequest-IEs } RRCSetupRequest-IEs :=  SEQUENCE {  ue-Identity     InitialUE-Identity,  establishmentCause    EstablishmentCause,  spare       BIT STRING (SIZE (1)) }InitialUE-Identity ::= CHOICE {  ng-5G-S-TMSI-Part1       BIT STRING(SIZE (39)),  random Value        BIT STRING (SIZE (39)) }EstablishmentCause ::=  ENUMERATED {        emergency,highPriorityAccess, mt- Access, mo-Signalling,        mo-Data,mo-VoiceCall, mo-VideoCall, mo-SMS, mps-Priority Access, mcs-PriorityAccess,        emergency roaming, spare5, spare4, spare3, spare2,spare1} -- TAG-RRCSETUPREQUEST-STOP -- ASN1STOP

Table 12 is a description of RRCSetupRequest-IE field.

TABLE 12 RRCSetupRequest-IEs field descriptions establishmentCauseProvides the establishment cause for the RRC request in accordance withthe information received from upper layers. gNB is not expected toreject a RRCSetupRequest due to unknown cause value being used by theUE. In case when a UE is trying to establish RRC connection due toemergency roaming, this can be indicated using this establishment cause.ue-Identity UE identity included to facilitate contention resolution bylower layers.

Table 13 is a description of InitialUE-Identity field.

TABLE 13 InitialUE-Identity field descriptions   ng-5G-S-TMSI-Part1 Therightmost 39 bits of 5G-S-TMSI. random Value Integer value in the range0 to 2³⁹ − 1.

That is, if any UE accesses other network due to a problem of HPLMN, theUE may set a cause value to disaster roaming and attempt a connection.

A disaster roaming cause is merely an example, and may be set to othervalue of a name or purpose similar to this. For example, in the case ofinternational roaming, if the UE attempts to access PLMN of MCC such asMCC of PLMN (network), to which the UE subscribes, using IMSI of the UE,the following cause field may be used.

Registration Request Procedure

Message Definition

The REGISTRATION REQUEST message is sent by the UE to the AMF. See Table8.2.6.1.1 of the standard document.

Message type: REGISTRATION REQUEST

Significance: dual

Direction: UE to network

Table 13 is Table 8.2.6.1.1 of the standard document, and illustratescomponents of the REGISTRATION REQUEST message.

TABLE 14 IEI Information Element Type/Reference Presence Format LengthExtended protocol Extended protocol discriminator M V 1 discriminator9.2 Security header type Security header type 9.3 M V ½ Spare half octetSpare half octet 9.5 M V ½ Registration request Message type 9.7 M V 1message identity 5GS registration type 5GS registration type 9.11.3.7 MLV 2 ngKSI NAS key set identifier 9.11.3.32 M V ½ Spare half octet Sparehalf octet 9.5 M V ½ 5GS mobile identity 5GS mobile identity 9.11.3.4 MLV 5-TBD C- Non-current native NAS NAS key set identifier 9.11.3.32 O TV1 key set identifier 10 5GMM capability 5GMM capability 9.11.3.1 O TLV3-15  2E UE security capability UE security capability 9.11.3.54 O TLV4-10  2F Requested NSSAI NSSAI 9.11.3.37 O TLV 4-74 52 Last visitedregistered 5GS tracking area identity O TV 7 TAI 9.11.3.8 65 S1 UEnetwork S1 UE network capability O TLV 4-15 capability 9.11.3.48 40Uplink data status Uplink data status 9.11.3.57 O TLV 4-34 50 PDUsession status PDU session status 9.11.3.44 O TLV 4-34 B- MICOindication MICO indication 9.11.3.31 O TV 1  2B UE status UE status9.11.3.56 O TLV 3  2C Additional GUTI 5GS mobile identity 9.11.3.4 O TLVTBD 25 Allowed PDU session Allowed PDU session status O TLV 4-34 status9.11.3.13 60 UE's usage setting UE's usage setting 9.11.3.55 O TLV 3 TBDRequested DRX DRX parameters 9.11.3.22 O TBD TBD parameters  7C EPS NASmessage EPS NAS message container O TLV-E TBD container 9.11.3.24  7ELADN indication LADN indication 9.11.3.29 O TLV-E 3-811  7B Payloadcontainer Payload container 9.11.3.39 O TLV-E 4-65538

The content of the REGISTRATION REQUEST message when a limited set ofIEs including those needed to establish security in the initial messagewhen it has no NAS security context is FFS.

5GS Registration Type

The purpose of the 5GS registration type information element is toindicate the type of the requested registration. The 5GS registrationtype information element is coded as shown in Tables 15 and 16. The 5GSregistration type is a type 4 information element with a length of 3octets.

TABLE 15 8 7 6 5 4 3 2 1 5GS registration type IEI octet 1 Length of 5GSregistration type contents octet 2 0 0 NG-RAN- FOR SMS 5GS registrationtype octet 3 Spare Spare RCU requested value

TABLE 16 5GS registration type value (octet 3, bits 1 to 3) Bits 3 2 1 00 1 initial registration 0 1 0 mobility registration updating 0 1 1periodic registration updating 1 0 0 disaster registration 1 0 1disaster roaming 1 1 1 reserved All other values are unused and shall beinterpreted as “initial registration”, if received by the network. SMSover NAS transport requested (SMS requested) (octet 3, bit 4) Bit 4 0SMS over NAS not supported 1 SMS over NAS supported Follow-on requestbit (FOR) (octet 3, bit 5) Bit 5 0 No follow-on request pending 1Follow-on request pending NG-RAN Radio Capability Update (NG-RAN-RCU)(octet 3, bit 6) Bit 6 0 NG-RAN radio capability update not needed 1NG-RAN radio capability update needed Bits 7 to 8 of octet 3 are spareand shall be coded as zero. Bits 7 to 8 of octet 3 are spare and shallbe coded as zero.

Similarly, even when the UE performs registration to the network usingan NAS message, the UE may inform emergency roaming via registrationtype information of the UE.

Preferably, in the above procedure, it may be based on PLMN codes thatthe UE includes information as above. That is, when the UE accesses aPLMN with the same MCC among UE's PLMN codes, the UE notifies performinga registration for an emergency reason as above, and does not notifyotherwise.

The present disclosure has been described based on HPLMN, but can beapplied to cases other than HPLMN.

Method 3

When a problem occurs in any communication network in any country in theabove procedure, the relevant agencies in each country define a casewhere communication services cannot be provided to UEs due to theproblem of the communication network as a disaster, and will try topromptly inform the general public of it. Thus, a server managing thecontents of a public warning system (PWS) composes a disaster textmessage and transmits it to each communication network, and thecommunication networks receiving it will transmit the PWS to the UEsover their own networks.

However, in the above operation, if a UE of the network (network A) inwhich the problem occurs is powered off or if the UE is not in thecoverage range of any network, the UE cannot receive the disaster textmessage transmitted by each network.

In particular, in order to prevent it, if each network indefinitelyrepeats transmission of the PWS, this becomes inefficient and is afactor of unnecessary waste of radio resources.

Method 3-1

Accordingly, the present disclosure is to propose a method forefficiently receiving, by all UEs, a disaster text message.

To this end, in the present disclosure, when any UE newly performsregistration to other network or performs registration to a network inother area of the same network, each UE may transmit information for thelast PWS received by the UE or information about whether the UE hasreceived the PWS. Based on this, if the network determines that the UEhas not received the PWS that the UE shall receive, the network may sendit to the UE.

Method 3-1-1

For example, when the UE performs a registration process to a networkover a new network (network B) or a new TA, the UE may transmitinformation for the last received PWS or identity information, and thisinformation may be a message ID. Unlike this, if there is nocorresponding information, the UE may inform the network that there isno corresponding information. Based on this, the network may compare itwith a message ID that the network has transmitted most recently, anddetermine whether the UE has properly received the latest PWS.

For example, when the UE performs a registration process to a networkover a new network (network B) or a new TA, the UE may transmitinformation related to a time at which the UE has received the last PWS,or area information. Based on this, the network may check a time atwhich the network has transmitted the PWS most recently, and determinewhether the UE has properly received the latest PWS.

Method 3-1-2

Based on the description in the method 3-1-1, if the network determinesthat the UE has not received latest information, the network may send aPWS message the network has stored, or inform a PWS transmission agencythat there is a UE that has not yet received the PWS. Hence, the networkmay allow the PWS transmission agency to perform retransmission.

Method 3-1-2-1

In the method 3-1-2, the network may store the previous PWS in order todirectly transmit the PWS to the UE. Alternatively, if the PWStransmission agency delegates it to the network, the PWS transmissionagency informs information, such as an identity of a related message,e.g., a message ID, together with the PWS message.

Method 3-1-2-2

In the method 3-1-2, if the network informs a PWS transmission agencythat there is a UE that has not yet received the PWS, the PWStransmission agency may determine not to retransmit the PWS to all theareas and to send a specific message only to the UE. In this case, thePWS may send a content of the PWS message to the network, and mayindicate that the network transmits it to only the UE.

The network receiving it sends the message to the UE using a textmessage, or sends the message to the UE using an NAS message.

Method 3-1-3

In order to support the description of the method 3-1, if each UEreceives a PWS message, the UE may store a message ID of each PWSmessage and a reception time of the PWS message in a memory, or managethem in the NAS message.

Method 3-1-4

In the operation of the method 3-1, only if the network indicates, viaSIB, etc. or via the NAS message, that the UE transmits the aboveinformation, the UE transmits information related to the PWS reception.

Method 3-1-5

The operation of the method 3-1 may also be automatically attempted whena network to which the UE has registered lastly is different from anetwork to which the UE is going to register currently. Alternatively,in a disaster roaming situation, when the UE accesses a new network, itmay be delivered.

Method 3-1-6

The operation of the method 3-1 may also be performed when time at whichthe UE cannot access any network or time at which the UE cannot find anynetwork is equal to or greater than a predetermined time.

Main Embodiments of the Present Disclosure

FIG. 15 is a flow chart illustrating a method for a UE to perform aregistration to a network in accordance with an embodiment of thepresent disclosure.

As illustrated in FIG. 15 , first, a UE may perform registration to afirst PLMN via a first base station, in S1501.

Next, when the UE can no longer receive services from the first PLMN(e.g., disaster generation), the UE may receive, from the first basestation, a message related to a disaster applied to the first PLMN orapplied to an area in which the UE is located, in S1503.

Next, the UE may perform registration to a second PLMN providing andisaster roaming service based on an disaster related message, in 51505.

FIG. 16 is a flow chart illustrating a method for a base station toregister a UE to a network in accordance with an embodiment of thepresent disclosure.

As illustrated in FIG. 16 , first, a base station may perform UE'sregistration to a first PLMN, in S1601.

Next, when the UE can no longer receive services from the first PLMN,the base station may send the UE a message related to a disaster appliedto the first PLMN or applied to an area in which the UE is located, inS1603.

Overview of Device to which the Present Disclosure is Applicable

FIG. 17 illustrates a block diagram of configuration of a communicationdevice according to an embodiment of the present disclosure.

Referring to FIG. 17 , a wireless communication system includes anetwork node 1710 and a plurality of UEs 1720.

The network node 1710 includes a processor 1711, a memory 1712, and acommunication module (or transceiver) 1713. The processor 1711 mayimplement functions, processes, and/or methods described above withreference to FIGS. 1 to 14 . Layers of wired/wireless interface protocolmay be implemented by the processor 1711.

The memory 1712 is connected to the processor 1711 and stores varioustypes of information for driving the processor 1711. The communicationmodule 1713 is connected to the processor 1711 and transmits and/orreceives wired/wireless signals. Examples of the network node 1710 mayinclude a base station, AMF, SMF, UDF, or the like. In particular, ifthe network node 1710 is the base station, the communication module 1713may include a radio frequency (RF) unit for transmitting/receiving aradio signal.

The UE 1720 includes a processor 1721, a memory 1722, and acommunication module (or RF unit) (or transceiver) 1723. The processor1721 may implement functions, processes and/or methods described abovewith reference to FIGS. 1 to 14 . Layers of a radio interface protocolmay be implemented by the processor 1721. In particular, the processor1721 may include the NAS layer and the AS layer. The memory 1722 isconnected to the processor 1721 and stores various types of informationfor driving the processor 1721. The communication module 1723 isconnected to the processor 1721 and transmits and/or receives a radiosignal.

The memories 1712 and 1722 may be inside or outside the processors 1711and 1721 and may be connected to the processors 1711 and 1721 throughvarious well-known means. Further, the network node 1710 (in case of thebase station) and/or the UE 1720 may have a single antenna or multipleantennas.

FIG. 18 illustrates a block diagram of configuration of a communicationdevice according to an embodiment of the present disclosure.

In particular, FIG. 18 illustrates in more detail the UE illustrated inFIG. 17 . The communication module illustrated in FIG. 17 includes an RFmodule (or RF unit) illustrated in FIG. 18 . The processor illustratedin FIG. 17 corresponds to a processor (or a digital signal processor(DSP) 1810) in FIG. 18 . The memory illustrated in FIG. 17 correspondsto a memory 1830 illustrated in FIG. 18 .

Referring to FIG. 18 , the UE may include a processor (or digital signalprocessor (DSP)) 1810, an RF module (or RF unit) 1835, a powermanagement module 1805, an antenna 1840, a battery 1855, a display 1815,a keypad 1820, a memory 1830, a subscriber identification module (SIM)card 1825 (which is optional), a speaker 1845, and a microphone 1850.The UE may also include a single antenna or multiple antennas.

The processor 1810 implements functions, processes, and/or methodsdescribed above. Layers of a radio interface protocol may be implementedby the processor 1810.

The memory 1830 is connected to the processor 1810 and storesinformation related to operations of the processor 1810. The memory 1830may be inside or outside the processor 1810 and may be connected to theprocessors 1810 through various well-known means.

A user inputs instructional information, such as a telephone number, forexample, by pushing (or touching) buttons of the keypad 1820 or by voiceactivation using the microphone 1850. The processor 1810 receives andprocesses the instructional information to perform an appropriatefunction, such as to dial the telephone number. Operational data may beextracted from the SIM card 1825 or the memory 1830. Further, theprocessor 1810 may display instructional information or operationalinformation on the display 1815 for the user's reference andconvenience.

The RF module 1835 is connected to the processor 1810 and transmitsand/or receives an RF signal. The processor 1810 forwards instructionalinformation to the RF module 1835 in order to initiate communication,for example, transmit a radio signal configuring voice communicationdata. The RF module 1835 includes a receiver and a transmitter toreceive and transmit the radio signal. The antenna 1840 functions totransmit and receive the radio signal. Upon reception of the radiosignal, the RF module 1835 may send a signal to be processed by theprocessor 1810 and convert the signal into a baseband. The processedsignal may be converted into audible or readable information output viathe speaker 1845.

FIG. 19 illustrates an example of a structure of a radio interfaceprotocol in a control plane between a UE and eNodeB.

The radio interface protocol is based on 3GPP radio access networkstandard. The radio interface protocol horizontally consists of aphysical layer, a data link layer, and a network layer, and isvertically divided into a user plane for data information transmissionand a control plane for control signaling delivery.

The protocol layers may be divided into L1 (first layer), L2 (secondlayer), and L3 (third layer) based on three lower layers of an opensystem interconnection (OSI) standard model that is well known in theart of communication systems.

The layers of the radio protocol in the control plane illustrated inFIG. 19 are described below.

The physical layer, the first layer, provides an information transferservice using a physical channel. The physical layer is connected to amedium access control (MAC) layer located at a higher level via atransport channel, and data between the MAC layer and the physical layeris transferred via the transport channel. Data is transferred betweendifferent physical layers, i.e., between physical layers of atransmission side and a reception side via the physical channel.

The physical channel consists of several subframes on a time axis andseveral subcarriers on a frequency axis. One subframe consists of aplurality of symbols and a plurality of subcarriers on the time axis.One subframe consists of a plurality of resource blocks, and oneresource block consists of a plurality of symbols and a plurality ofsubcarriers. A unit time, a transmission time interval (TTI), at whichdata is transmitted, is 1 ms corresponding to one subframe.

Physical channels existing in the physical layers of the transmissionside and the reception side may be divided into, according to 3GPP LTE,a physical downlink shared channel (PDSCH) and a physical uplink sharedchannel (PUSCH) that are data channels, and a physical downlink controlchannel (PDCCH), a physical control format indicator channel (PCFICH), aphysical hybrid-ARQ indicator channel (PHICH), and a physical uplinkcontrol channel (PUCCH) that are control channels.

The PCFICH transmitted on a first OFDM symbol of a subframe carries acontrol format indicator (CFI) regarding the number of OFDM symbols usedfor transmission of control channels in the subframe (i.e., size of acontrol region). A wireless device first receives the CFI on the PCFICHand then monitors the PDCCH.

Unlike the PDCCH, the PCFICH is transmitted via a fixed PCFICH resourceof the subframe without the use of blind decoding.

The PHICH carries positive acknowledgement (ACK)/negativeacknowledgement (NACK) signal for uplink (UL) hybrid automatic repeatrequest (HARQ). The ACK/NACK signal for UL data on PUSCH transmitted bythe wireless device is transmitted on the PHICH.

A physical broadcast channel (PBCH) is transmitted on first four OFDMsymbols of a second slot of a first subframe of a radio frame. The PBCHcarries system information essential for the wireless device tocommunicate with the base station, and system information transmitted onthe PBCH is referred to as a master information block (MIB). Compared tothis, system information transmitted on the PDSCH indicated by the PDCCHis referred to as a system information block (SIB).

The PDCCH may carry resource allocation and transport format of adownlink shared channel (DL-SCH), resource allocation information of anuplink shared channel (UL-SCH), paging information on a paging channel(PCH), system information on DL-SCH, resource allocation of an upperlayer control message such as a random access response transmitted onPDSCH, a set of Tx power control commands on individual UEs within anarbitrary UE group, a Tx power control command, activation of a voiceover internet protocol (VoIP), etc. A plurality of PDCCHs can betransmitted within a control region, and the UE can monitor theplurality of PDCCHs. The PDCCH is transmitted on aggregation of one ormultiple consecutive control channel elements (CCEs). The CCE is alogical allocation unit used to provide the PDCCH with a coding ratebased on a state of a radio channel. The CCE corresponds to a pluralityof resource element groups. A format of the PDCCH and the number of bitsof the available PDCCH are determined depending on a correlation betweenthe number of CCEs and the coding rate provided by the CCEs.

Control information transmitted on PDCCH is referred to as downlinkcontrol information (DCI). The DCI may contain resource allocation ofPDSCH (which is also referred to as DL grant), resource allocation ofPUSCH (which is also referred to as UL grant), a set of Tx power controlcommands on individual UEs within an arbitrary UE group, and/oractivation of a voice over internet protocol (VoIP).

There are several layers in the second layer. First, a medium accesscontrol (MAC) layer functions to map various logical channels to varioustransfer channels, and also performs a function of logical channelmultiplexing for mapping several logical channels to one transferchannel. The MAC layer is connected to a radio link control (RLC) layer,that is an upper layer, via the logical channel. The logical channel isroughly divided into a control channel used to transmit information ofthe control plane and a traffic channel used to transmit information ofthe user plane, according to a type of transmitted information.

The radio link control (RLC) layer of the second layer segments andconcatenate data received from the upper layer and adjusts a data sizeso that a lower layer is adapted to transmit data to a radio section. Inorder to guarantee various QoS required by each radio bearer (RB), theRLC layer provides three operation modes of a transparent mode (TM), anunacknowledged mode (UM) (non-response mode), and an acknowledged mode(AM) (or response mode). In particular, the AM RLC performs aretransmission function through an automatic repeat and request (ARQ)function for reliable data transmission.

A packet data convergence protocol (PDCP) layer of the second layerperforms a header compression function of reducing an IP packet headersize that has a relatively large size and contains unnecessary controlinformation, in order to efficiently transmit data in a radio sectionhaving a small bandwidth upon transmission of IP packet such as IPv4 orIPv6. This allows only information, that is necessarily required in aheader part of data, to be transmitted, thereby increasing transmissionefficiency of the radio section. In the LTE system, the PDCP layer alsoperforms a security function, which consists of ciphering for preventingdata interception by a third party and integrity protection forpreventing data manipulation by a third party.

A radio resource control (RRC) layer located at the uppermost part ofthe third layer is defined only in the control plane and is responsiblefor controlling logical channels, transport channels, and physicalchannels in relation to configuration, re-configuration, and release ofradio bearers (RBs). The RB means services provided by the second layerto ensure data transfer between the UE and the E-UTRAN.

If an RRC connection is established between an RRC layer of the UE andan RRC layer of a wireless network, the UE is in an RRC connected mode.Otherwise, the UE is in an RRC idle mode.

An RRC state of the UE and an RRC connection method are described below.The RRC state refers to a state in which the RRC of the UE is or is notlogically connected with the RRC of the E-UTRAN. The RRC state of the UEhaving logical connection with the RRC of the E-UTRAN is referred to asan RRC_CONNECTED state, and the RRC state of the UE not having logicalconnection with the RRC of the E-UTRAN is referred to as an RRC_IDLEstate. Since the UE in the RRC_CONNECTED state has the RRC connection,the E-UTRAN can identify the presence of the corresponding UE on a percell basis and thus efficiently control the UE. On the other hand, theE-UTRAN cannot identify the presence of the UE of the RRC_IDLE state,and the UE in the RRC_IDLE state is managed by a core network based on atracking area (TA) which is an area unit larger than the cell. That is,for the UE in the RRC_IDLE state, only presence or absence of thecorresponding UE is identified in an area unit larger than the cell. Inorder for the UE of the RRC_IDLE state to receive typical mobilecommunication services such as voice and data, the UE should transitionto the RRC_CONNECTED state. Each TA is distinguished from another TA bya tracking area identity (TAI) thereof. The UE may configure the TAIthrough a tracking area code (TAC) which is information broadcasted froma cell.

When the user initially turns on the UE, the UE first searches for aproper cell, and then establishes RRC connection in the correspondingcell and registers information of the UE in the core network.Thereafter, the UE stays in the RRC_IDLE state. The UE staying in theRRC_IDLE state (re)selects a cell and checks system information orpaging information, if necessary. This operation is called camping on acell. Only when the UE staying in the RRC_IDLE state needs to establishthe RRC connection, the UE establishes the RRC connection with the RRClayer of the E-UTRAN through a RRC connection procedure and transitionsto the RRC_CONNECTED state. There are several cases where the UEremaining in the RRC_IDLE state needs to establish the RRC connection.Examples of the cases may include a case where transmission of uplinkdata is necessary for a reason of an attempt of a user to make a phonecall, etc., or transmission of a response message when receiving apaging signal from the E-UTRAN.

A non-access stratum (NAS) layer performs functions such as sessionmanagement and mobility management.

The NAS layer illustrated in FIG. 19 is described in detail below.

The NAS layer is divided into a NAS entity for mobility management (MM)and a NAS entity for session management (SM).

1) The NAS entity for MM generally provides the following functions.

An NAS procedure related to the AMF includes the following.

-   -   Registration management and connection management procedure. The        AMF supports the functions.    -   Secure NAS signal connection between the UE and the AMF        (integrity protection, ciphering)

2) The NAS entity for SM performs session management between the UE andthe SMF.

A SM signalling message is generated and processed in the UE and theNAS-SM layer of the SMF. The content of the SM signalling message is notinterpreted by the AMF.

-   -   In case of SM signalling transmission,    -   The NAS entity for MM generates security header indicating NAS        transmission of SM signalling, and a NAS-MM message deriving a        method and location of sending the SM signalling message via        additional information for the received NAS-MM.    -   Upon reception of SM signalling, the NAS entity for SM performs        integrity check of the NAS-MM message, and derives a method and        place of deriving the SM signalling message by interpreting        additional information.

In FIG. 19 , the RRC layer, the RLC layer, the MAC layer, and the PHYlayer located below the NAS layer are collectively referred to accessstratum (AS) layer.

Application Range of the Present Disclosure

A wireless device in the present disclosure may be a base station, anetwork node, a transmitter UE, a receiver UE, a radio device, awireless communication device, a vehicle, a vehicle with a self-drivingfunction, a drone (unmanned aerial vehicle (UAV)), an artificialintelligence (AI) module, a robot, an augmented reality (AR) device, avirtual reality (VR) device, an MTC device, an IoT device, a medicaldevice, a FinTech device (or financial device), a security device, aclimate/environment device, or a device related to the fourth industrialrevolution field or 5G service, or the like. For example, the drone maybe an airborne vehicle that flies by a radio control signal without aperson being on the flight vehicle. For example, the MTC device and theIoT device may be a device that does not require a person's directintervention or manipulation, and may include a smart meter, a vendingmachine, a thermometer, a smart bulb, a door lock, a variety of sensors,or the like. For example, the medical device may be a device used forthe purpose of diagnosing, treating, reducing, handling or preventing adisease and a device used for the purpose of testing, substituting ormodifying a structure or function, and may include a device for medicaltreatment, a device for operation, a device for (external) diagnosis, ahearing aid, or a device for a surgical procedure, or the like. Forexample, the security device may be a device installed to prevent apossible danger and to maintain safety, and may include a camera, CCTV,a black box, or the like. For example, the FinTech device may be adevice capable of providing financial services, such as mobile payment,and may include a payment device, point of sales (POS), or the like. Forexample, the climate/environment device may refer to a device formonitoring and predicting the climate/environment.

Mobile terminals disclosed in the present disclosure may includecellular phones, smart phones, laptop computers, digital broadcastterminals, personal digital assistants (PDAs), portable multimediaplayers (PMPs), navigators, slate PCs, tablet PCs, ultra-books, wearabledevices (e.g., smart watches, smart glasses, head mounted displays(HMDs)), and the like. Furthermore, the mobile terminals may be used forcontrolling at least one device in an Internet of Things (IoT)environment or a smart greenhouse.

By way of non-limiting example only, further description will be madewith reference to particular types of mobile terminals. However, suchteachings may be equally applied to other types of mobile terminals,such as those types noted above. In addition, it can be readily apparentto those skilled in the art that these teachings can also be applied tostationary terminals such as digital TV, desktop computers, digitalsignage, and the like.

Hereinafter, embodiments related to a control method which can beimplemented by the mobile terminal configured as above were describedwith reference to the accompanying drawings. It is apparent to thoseskilled in the art that various modifications can be made to within therange without departing from the spirit and essential features of thepresent invention.

The embodiments of the present disclosure described above can beimplemented by various means. For example, embodiments of the presentdisclosure can be implemented by hardware, firmware, software, orcombinations thereof.

When embodiments are implemented by hardware, a method according toembodiments of the present disclosure can be implemented by one or moreapplication specific integrated circuits (ASICs), digital signalprocessors (DSPs), digital signal processing devices (DSPDs),programmable logic devices (PLDs), field programmable gate arrays(FPGAs), processors, controllers, microcontrollers, microprocessors, andthe like.

When embodiments are implemented by firmware or software, a methodaccording to embodiments of the present disclosure can be implemented bydevices, procedures, functions, etc. performing functions or operationsdescribed above. Software code can be stored in a memory unit and can beexecuted by a processor. The memory unit is provided inside or outsidethe processor and can exchange data with the processor by variouswell-known means.

The present disclosure described above can be implemented using acomputer-readable medium with programs recorded thereon for execution bya processor to perform various methods presented herein. Thecomputer-readable medium includes all kinds of recording devices capableof storing data that is readable by a computer system. Examples of thecomputer-readable mediums include hard disk drive (HDD), solid statedisk (SSD), silicon disk drive (SDD), ROM, RAM, CD-ROM, a magnetic tape,a floppy disk, and an optical data storage device, other types ofstorage mediums presented herein, etc. If desired, the computer-readablemedium may be implemented in the form of a carrier wave (e.g.,transmission over Internet). The computer may include the processor ofthe terminal. Accordingly, the detailed description should not beconstrued as limiting in all aspects and should be considered asillustrative. The scope of the present disclosure should be determinedby rational interpretation of the appended claims, and all modificationswithin an equivalent scope of the present disclosure are included in thescope of the present disclosure.

INDUSTRIAL APPLICABILITY

The communication method described above can be applied to variouswireless communication systems including IEEE 802.16x and 802.11xsystems, in addition to the 3GPP system. Furthermore, the proposedmethod can be applied to the mmWave communication system usingultra-high frequency bands.

The invention claimed is:
 1. A method performed, by a user equipment(UE) in a wireless communication system, the method comprising:selecting a public land mobile network (PLMN); transmitting, to thePLMN, a registration request message; and receiving, from the PLMN, aregistration accept message, wherein the registration request messageincludes information for a registration type, wherein the informationfor the registration type represents one among a plurality of 3-bitvalues related to a type of a requested registration, and wherein, basedon the information for the registration type representing a 3-bit valuewhich is configured for a disaster roaming, the UE is provided with adisaster roaming service from the PLMN based on a disaster conditionapplied to a home PLMN (HPLMN) of the UE.
 2. The method of claim 1,wherein the disaster condition is related to an area in which the UE islocated.
 3. A user equipment (UE) configured to operate in a wirelesscommunication system, the UE comprising: an RF module configured totransmit and receive a radio signal; at least one processor functionallyconnected to the RF module; and at least one computer memoryoperationally connected to the at least one processor, wherein the atleast one computer memory stores instructions that, based on beingexecuted by the at least one processor, perform operations comprising:selecting a public land mobile network (PLMN); transmitting, to thePLMN, a registration request message; and receiving, from the PLMN, aregistration accept message, wherein the registration request messageincludes information for a registration type, wherein the informationfor the registration type represents one among a plurality of 3-bitvalues related to a type of a requested registration, and wherein, basedon the information for the registration type representing a 3-bit valuewhich is configured for a disaster roaming, the UE is provided with adisaster roaming service from the PLMN based on a disaster conditionapplied to a home PLMN (HPLMN) of the UE.
 4. The UE of claim 3, whereinthe disaster condition is related to an area in which the UE is located.5. At least one non-transitory computer-readable media storinginstructions that, based on being executed by at least one processor,perform operations comprising: selecting a first public land mobilenetwork (PLMN); transmitting, to the PLMN, a registration requestmessage; and receiving, from the PLMN, a registration accept message,wherein the registration request message includes information for aregistration type, wherein the information for the registration typerepresents one among a plurality of 3-bit values related to a type of arequested registration, and wherein, based on the information for theregistration type representing a 3-bit value which is configured for adisaster roaming, a user equipment (UE) is provided with a disasterroaming service from the PLMN based on a disaster condition applied to ahome PLMN (HPLMN) of the UE.